229539
How many compound given below are amphoteric oxides? $\mathrm{P}_2 \mathrm{O}_5, \mathrm{P}_4 \mathrm{O}_6, \mathrm{As}_2 \mathrm{O}_5, \mathrm{As}_4 \mathrm{O}_6, \mathrm{Sb}_2 \mathrm{O}_5, \mathrm{Sb}_4 \mathrm{O}_6, \mathrm{Bi}_2 \mathrm{O}_3$
1 2
2 3
3 4
4 6
Explanation:
The oxides of the type $\mathrm{E}_2 \mathrm{O}_3$ of $\mathrm{N}$ and $P$, $\mathrm{P}_2 \mathrm{O}_3\left(\mathrm{P}_4 \mathrm{O}_6\right.$, dimer of $\left.\mathrm{P}_2 \mathrm{O}_3\right)$ are purely acidic, that of $\mathrm{As}$ $\left(\mathrm{As}_4 \mathrm{O}_6\right.$, dimer of $\left.\mathrm{As}_2 \mathrm{O}_3\right)$ and $\mathrm{Sb}\left(\mathrm{Sb}_4 \mathrm{O}_6\right.$, dimer of $\left.\mathrm{Sb}_2 \mathrm{O}_3\right)$ amphoteric and that of $\mathrm{Bi}\left(\mathrm{Bi}_2 \mathrm{O}_3\right)$ is predominantly basic. The oxides of the type $\mathrm{E}_2 \mathrm{O}_3$ are more acidic, e.g. $\mathrm{N}_2 \mathrm{O}_3$, $\mathrm{P}_2 \mathrm{O}_5, \mathrm{As}_2 \mathrm{O}_5, \mathrm{Sb}_2 \mathrm{O}_5$ So, in the given set of oxides of group- 15 elements, two oxides are amphoteric, $\mathrm{As}_4 \mathrm{O}_6$ and $\mathrm{Sb}_4 \mathrm{O}_6$.
Shift-II
Ionic Equilibrium
229540
Which acid among the following has the highest $\mathrm{pK}_{\mathrm{a}}$ value ?
1 $\mathrm{HC} \ell$
2 $\mathrm{HF}$
3 $\mathrm{H} \ell$
4 $\mathrm{HBr}$
Explanation:
$\mathrm{HF}\left(\mathrm{pK}_{\mathrm{a}}=3.1\right.$ ) $\mathrm{HCl}\left(\mathrm{pK}_{\mathrm{a}}=-6.0\right)$ $\mathrm{HBr}\left(\mathrm{pK}_{\mathrm{a}}=-9.0\right)$ $\mathrm{HI}\left(\mathrm{pK}_{\mathrm{a}}=-9.5\right)$ Therefore, $\mathrm{HF}$ has highest $\mathrm{pK}_{\mathrm{a}}$ value. Hence, the correct option is (b).
Shift-I
Ionic Equilibrium
229546
Using the Lewis concept, which one of the following has the strongest acidic strength ?
1 $\mathrm{H}_3 \mathrm{PO}_4$
2 $\mathrm{H}_3 \mathrm{PO}_3$
3 $\mathrm{H}_3 \mathrm{PO}_2$
4 All are of equal strength
Explanation:
$\mathrm{H}_3 \mathrm{PO}_4$ has the strongest acid strength as the no. of $\mathrm{O}$ atom is more in case of $\mathrm{H}_3 \mathrm{PO}_4$. As the no. of $\mathrm{O}$ atom increases the strength of the acid increases. Oxygen is highly electronegative element, and so if there are more $\mathrm{O}$ atoms present, more will be the electron pulling tendency. So, $\mathrm{O}-\mathrm{H}$ bond weakening results more acidic character.
SCRA-2009
Ionic Equilibrium
229547
$\mathrm{SiCl}_4$ on hydrolysis forms ' $\mathrm{X}$ ' and $\mathrm{HCl}$, compound ' $\mathrm{X}$ ' losses water at $1000^{\circ} \mathrm{C}$ and gives ' $Y$ '. Compounds ' $X$ ' and ' $Y$ ' respectively are
1 $\mathrm{H}_2 \mathrm{SiCl}_6, \mathrm{SiO}_2$
2 $\mathrm{H}_4 \mathrm{SiO}_4, \mathrm{Si}$
3 $\mathrm{SiO}_2, \mathrm{Si}$
4 $\mathrm{H}_4 \mathrm{SiO}_4, \mathrm{SiO}_2$
Explanation:
$\mathrm{SiCl}_4$ on hydrolysis give $\mathrm{H}_2 \mathrm{SiO}_4$ $\mathrm{SiCl}_4+4 \mathrm{H}_2 \mathrm{O} \rightarrow \mathrm{H}_2 \mathrm{SiO}_3+4 \mathrm{HCl}$ $\mathrm{H}_4 \mathrm{SiO}_4$ loses the water at 1000 degree centigrade and produces $\mathrm{SiO}_2$ $\mathrm{H}_4 \mathrm{SiO}_4 \rightarrow \mathrm{SiO}_2+2 \mathrm{H}_2 \mathrm{O}$ So, $\mathrm{X}$ and $\mathrm{Y}$ are $\mathrm{H}_4 \mathrm{SiO}_4$ and $\mathrm{SiO}_2$ respectively.
AP EAMCET (Engg.)-2009
Ionic Equilibrium
229548
Which of the following does not form double salts?
1 $\mathrm{Li}_2 \mathrm{SO}_4$
2 $\mathrm{Na}_2 \mathrm{SO}_4$
3 $\mathrm{K}_2 \mathrm{SO}_4$
4 $\mathrm{Rb}_2 \mathrm{SO}_4$
Explanation:
Double salt is salt that contains more than one different contains or anion it completely dissociate into simple ions. Lithium is an electropositive element. It has vary small size. It cannot form double salt.
229539
How many compound given below are amphoteric oxides? $\mathrm{P}_2 \mathrm{O}_5, \mathrm{P}_4 \mathrm{O}_6, \mathrm{As}_2 \mathrm{O}_5, \mathrm{As}_4 \mathrm{O}_6, \mathrm{Sb}_2 \mathrm{O}_5, \mathrm{Sb}_4 \mathrm{O}_6, \mathrm{Bi}_2 \mathrm{O}_3$
1 2
2 3
3 4
4 6
Explanation:
The oxides of the type $\mathrm{E}_2 \mathrm{O}_3$ of $\mathrm{N}$ and $P$, $\mathrm{P}_2 \mathrm{O}_3\left(\mathrm{P}_4 \mathrm{O}_6\right.$, dimer of $\left.\mathrm{P}_2 \mathrm{O}_3\right)$ are purely acidic, that of $\mathrm{As}$ $\left(\mathrm{As}_4 \mathrm{O}_6\right.$, dimer of $\left.\mathrm{As}_2 \mathrm{O}_3\right)$ and $\mathrm{Sb}\left(\mathrm{Sb}_4 \mathrm{O}_6\right.$, dimer of $\left.\mathrm{Sb}_2 \mathrm{O}_3\right)$ amphoteric and that of $\mathrm{Bi}\left(\mathrm{Bi}_2 \mathrm{O}_3\right)$ is predominantly basic. The oxides of the type $\mathrm{E}_2 \mathrm{O}_3$ are more acidic, e.g. $\mathrm{N}_2 \mathrm{O}_3$, $\mathrm{P}_2 \mathrm{O}_5, \mathrm{As}_2 \mathrm{O}_5, \mathrm{Sb}_2 \mathrm{O}_5$ So, in the given set of oxides of group- 15 elements, two oxides are amphoteric, $\mathrm{As}_4 \mathrm{O}_6$ and $\mathrm{Sb}_4 \mathrm{O}_6$.
Shift-II
Ionic Equilibrium
229540
Which acid among the following has the highest $\mathrm{pK}_{\mathrm{a}}$ value ?
1 $\mathrm{HC} \ell$
2 $\mathrm{HF}$
3 $\mathrm{H} \ell$
4 $\mathrm{HBr}$
Explanation:
$\mathrm{HF}\left(\mathrm{pK}_{\mathrm{a}}=3.1\right.$ ) $\mathrm{HCl}\left(\mathrm{pK}_{\mathrm{a}}=-6.0\right)$ $\mathrm{HBr}\left(\mathrm{pK}_{\mathrm{a}}=-9.0\right)$ $\mathrm{HI}\left(\mathrm{pK}_{\mathrm{a}}=-9.5\right)$ Therefore, $\mathrm{HF}$ has highest $\mathrm{pK}_{\mathrm{a}}$ value. Hence, the correct option is (b).
Shift-I
Ionic Equilibrium
229546
Using the Lewis concept, which one of the following has the strongest acidic strength ?
1 $\mathrm{H}_3 \mathrm{PO}_4$
2 $\mathrm{H}_3 \mathrm{PO}_3$
3 $\mathrm{H}_3 \mathrm{PO}_2$
4 All are of equal strength
Explanation:
$\mathrm{H}_3 \mathrm{PO}_4$ has the strongest acid strength as the no. of $\mathrm{O}$ atom is more in case of $\mathrm{H}_3 \mathrm{PO}_4$. As the no. of $\mathrm{O}$ atom increases the strength of the acid increases. Oxygen is highly electronegative element, and so if there are more $\mathrm{O}$ atoms present, more will be the electron pulling tendency. So, $\mathrm{O}-\mathrm{H}$ bond weakening results more acidic character.
SCRA-2009
Ionic Equilibrium
229547
$\mathrm{SiCl}_4$ on hydrolysis forms ' $\mathrm{X}$ ' and $\mathrm{HCl}$, compound ' $\mathrm{X}$ ' losses water at $1000^{\circ} \mathrm{C}$ and gives ' $Y$ '. Compounds ' $X$ ' and ' $Y$ ' respectively are
1 $\mathrm{H}_2 \mathrm{SiCl}_6, \mathrm{SiO}_2$
2 $\mathrm{H}_4 \mathrm{SiO}_4, \mathrm{Si}$
3 $\mathrm{SiO}_2, \mathrm{Si}$
4 $\mathrm{H}_4 \mathrm{SiO}_4, \mathrm{SiO}_2$
Explanation:
$\mathrm{SiCl}_4$ on hydrolysis give $\mathrm{H}_2 \mathrm{SiO}_4$ $\mathrm{SiCl}_4+4 \mathrm{H}_2 \mathrm{O} \rightarrow \mathrm{H}_2 \mathrm{SiO}_3+4 \mathrm{HCl}$ $\mathrm{H}_4 \mathrm{SiO}_4$ loses the water at 1000 degree centigrade and produces $\mathrm{SiO}_2$ $\mathrm{H}_4 \mathrm{SiO}_4 \rightarrow \mathrm{SiO}_2+2 \mathrm{H}_2 \mathrm{O}$ So, $\mathrm{X}$ and $\mathrm{Y}$ are $\mathrm{H}_4 \mathrm{SiO}_4$ and $\mathrm{SiO}_2$ respectively.
AP EAMCET (Engg.)-2009
Ionic Equilibrium
229548
Which of the following does not form double salts?
1 $\mathrm{Li}_2 \mathrm{SO}_4$
2 $\mathrm{Na}_2 \mathrm{SO}_4$
3 $\mathrm{K}_2 \mathrm{SO}_4$
4 $\mathrm{Rb}_2 \mathrm{SO}_4$
Explanation:
Double salt is salt that contains more than one different contains or anion it completely dissociate into simple ions. Lithium is an electropositive element. It has vary small size. It cannot form double salt.
229539
How many compound given below are amphoteric oxides? $\mathrm{P}_2 \mathrm{O}_5, \mathrm{P}_4 \mathrm{O}_6, \mathrm{As}_2 \mathrm{O}_5, \mathrm{As}_4 \mathrm{O}_6, \mathrm{Sb}_2 \mathrm{O}_5, \mathrm{Sb}_4 \mathrm{O}_6, \mathrm{Bi}_2 \mathrm{O}_3$
1 2
2 3
3 4
4 6
Explanation:
The oxides of the type $\mathrm{E}_2 \mathrm{O}_3$ of $\mathrm{N}$ and $P$, $\mathrm{P}_2 \mathrm{O}_3\left(\mathrm{P}_4 \mathrm{O}_6\right.$, dimer of $\left.\mathrm{P}_2 \mathrm{O}_3\right)$ are purely acidic, that of $\mathrm{As}$ $\left(\mathrm{As}_4 \mathrm{O}_6\right.$, dimer of $\left.\mathrm{As}_2 \mathrm{O}_3\right)$ and $\mathrm{Sb}\left(\mathrm{Sb}_4 \mathrm{O}_6\right.$, dimer of $\left.\mathrm{Sb}_2 \mathrm{O}_3\right)$ amphoteric and that of $\mathrm{Bi}\left(\mathrm{Bi}_2 \mathrm{O}_3\right)$ is predominantly basic. The oxides of the type $\mathrm{E}_2 \mathrm{O}_3$ are more acidic, e.g. $\mathrm{N}_2 \mathrm{O}_3$, $\mathrm{P}_2 \mathrm{O}_5, \mathrm{As}_2 \mathrm{O}_5, \mathrm{Sb}_2 \mathrm{O}_5$ So, in the given set of oxides of group- 15 elements, two oxides are amphoteric, $\mathrm{As}_4 \mathrm{O}_6$ and $\mathrm{Sb}_4 \mathrm{O}_6$.
Shift-II
Ionic Equilibrium
229540
Which acid among the following has the highest $\mathrm{pK}_{\mathrm{a}}$ value ?
1 $\mathrm{HC} \ell$
2 $\mathrm{HF}$
3 $\mathrm{H} \ell$
4 $\mathrm{HBr}$
Explanation:
$\mathrm{HF}\left(\mathrm{pK}_{\mathrm{a}}=3.1\right.$ ) $\mathrm{HCl}\left(\mathrm{pK}_{\mathrm{a}}=-6.0\right)$ $\mathrm{HBr}\left(\mathrm{pK}_{\mathrm{a}}=-9.0\right)$ $\mathrm{HI}\left(\mathrm{pK}_{\mathrm{a}}=-9.5\right)$ Therefore, $\mathrm{HF}$ has highest $\mathrm{pK}_{\mathrm{a}}$ value. Hence, the correct option is (b).
Shift-I
Ionic Equilibrium
229546
Using the Lewis concept, which one of the following has the strongest acidic strength ?
1 $\mathrm{H}_3 \mathrm{PO}_4$
2 $\mathrm{H}_3 \mathrm{PO}_3$
3 $\mathrm{H}_3 \mathrm{PO}_2$
4 All are of equal strength
Explanation:
$\mathrm{H}_3 \mathrm{PO}_4$ has the strongest acid strength as the no. of $\mathrm{O}$ atom is more in case of $\mathrm{H}_3 \mathrm{PO}_4$. As the no. of $\mathrm{O}$ atom increases the strength of the acid increases. Oxygen is highly electronegative element, and so if there are more $\mathrm{O}$ atoms present, more will be the electron pulling tendency. So, $\mathrm{O}-\mathrm{H}$ bond weakening results more acidic character.
SCRA-2009
Ionic Equilibrium
229547
$\mathrm{SiCl}_4$ on hydrolysis forms ' $\mathrm{X}$ ' and $\mathrm{HCl}$, compound ' $\mathrm{X}$ ' losses water at $1000^{\circ} \mathrm{C}$ and gives ' $Y$ '. Compounds ' $X$ ' and ' $Y$ ' respectively are
1 $\mathrm{H}_2 \mathrm{SiCl}_6, \mathrm{SiO}_2$
2 $\mathrm{H}_4 \mathrm{SiO}_4, \mathrm{Si}$
3 $\mathrm{SiO}_2, \mathrm{Si}$
4 $\mathrm{H}_4 \mathrm{SiO}_4, \mathrm{SiO}_2$
Explanation:
$\mathrm{SiCl}_4$ on hydrolysis give $\mathrm{H}_2 \mathrm{SiO}_4$ $\mathrm{SiCl}_4+4 \mathrm{H}_2 \mathrm{O} \rightarrow \mathrm{H}_2 \mathrm{SiO}_3+4 \mathrm{HCl}$ $\mathrm{H}_4 \mathrm{SiO}_4$ loses the water at 1000 degree centigrade and produces $\mathrm{SiO}_2$ $\mathrm{H}_4 \mathrm{SiO}_4 \rightarrow \mathrm{SiO}_2+2 \mathrm{H}_2 \mathrm{O}$ So, $\mathrm{X}$ and $\mathrm{Y}$ are $\mathrm{H}_4 \mathrm{SiO}_4$ and $\mathrm{SiO}_2$ respectively.
AP EAMCET (Engg.)-2009
Ionic Equilibrium
229548
Which of the following does not form double salts?
1 $\mathrm{Li}_2 \mathrm{SO}_4$
2 $\mathrm{Na}_2 \mathrm{SO}_4$
3 $\mathrm{K}_2 \mathrm{SO}_4$
4 $\mathrm{Rb}_2 \mathrm{SO}_4$
Explanation:
Double salt is salt that contains more than one different contains or anion it completely dissociate into simple ions. Lithium is an electropositive element. It has vary small size. It cannot form double salt.
NEET Test Series from KOTA - 10 Papers In MS WORD
WhatsApp Here
Ionic Equilibrium
229539
How many compound given below are amphoteric oxides? $\mathrm{P}_2 \mathrm{O}_5, \mathrm{P}_4 \mathrm{O}_6, \mathrm{As}_2 \mathrm{O}_5, \mathrm{As}_4 \mathrm{O}_6, \mathrm{Sb}_2 \mathrm{O}_5, \mathrm{Sb}_4 \mathrm{O}_6, \mathrm{Bi}_2 \mathrm{O}_3$
1 2
2 3
3 4
4 6
Explanation:
The oxides of the type $\mathrm{E}_2 \mathrm{O}_3$ of $\mathrm{N}$ and $P$, $\mathrm{P}_2 \mathrm{O}_3\left(\mathrm{P}_4 \mathrm{O}_6\right.$, dimer of $\left.\mathrm{P}_2 \mathrm{O}_3\right)$ are purely acidic, that of $\mathrm{As}$ $\left(\mathrm{As}_4 \mathrm{O}_6\right.$, dimer of $\left.\mathrm{As}_2 \mathrm{O}_3\right)$ and $\mathrm{Sb}\left(\mathrm{Sb}_4 \mathrm{O}_6\right.$, dimer of $\left.\mathrm{Sb}_2 \mathrm{O}_3\right)$ amphoteric and that of $\mathrm{Bi}\left(\mathrm{Bi}_2 \mathrm{O}_3\right)$ is predominantly basic. The oxides of the type $\mathrm{E}_2 \mathrm{O}_3$ are more acidic, e.g. $\mathrm{N}_2 \mathrm{O}_3$, $\mathrm{P}_2 \mathrm{O}_5, \mathrm{As}_2 \mathrm{O}_5, \mathrm{Sb}_2 \mathrm{O}_5$ So, in the given set of oxides of group- 15 elements, two oxides are amphoteric, $\mathrm{As}_4 \mathrm{O}_6$ and $\mathrm{Sb}_4 \mathrm{O}_6$.
Shift-II
Ionic Equilibrium
229540
Which acid among the following has the highest $\mathrm{pK}_{\mathrm{a}}$ value ?
1 $\mathrm{HC} \ell$
2 $\mathrm{HF}$
3 $\mathrm{H} \ell$
4 $\mathrm{HBr}$
Explanation:
$\mathrm{HF}\left(\mathrm{pK}_{\mathrm{a}}=3.1\right.$ ) $\mathrm{HCl}\left(\mathrm{pK}_{\mathrm{a}}=-6.0\right)$ $\mathrm{HBr}\left(\mathrm{pK}_{\mathrm{a}}=-9.0\right)$ $\mathrm{HI}\left(\mathrm{pK}_{\mathrm{a}}=-9.5\right)$ Therefore, $\mathrm{HF}$ has highest $\mathrm{pK}_{\mathrm{a}}$ value. Hence, the correct option is (b).
Shift-I
Ionic Equilibrium
229546
Using the Lewis concept, which one of the following has the strongest acidic strength ?
1 $\mathrm{H}_3 \mathrm{PO}_4$
2 $\mathrm{H}_3 \mathrm{PO}_3$
3 $\mathrm{H}_3 \mathrm{PO}_2$
4 All are of equal strength
Explanation:
$\mathrm{H}_3 \mathrm{PO}_4$ has the strongest acid strength as the no. of $\mathrm{O}$ atom is more in case of $\mathrm{H}_3 \mathrm{PO}_4$. As the no. of $\mathrm{O}$ atom increases the strength of the acid increases. Oxygen is highly electronegative element, and so if there are more $\mathrm{O}$ atoms present, more will be the electron pulling tendency. So, $\mathrm{O}-\mathrm{H}$ bond weakening results more acidic character.
SCRA-2009
Ionic Equilibrium
229547
$\mathrm{SiCl}_4$ on hydrolysis forms ' $\mathrm{X}$ ' and $\mathrm{HCl}$, compound ' $\mathrm{X}$ ' losses water at $1000^{\circ} \mathrm{C}$ and gives ' $Y$ '. Compounds ' $X$ ' and ' $Y$ ' respectively are
1 $\mathrm{H}_2 \mathrm{SiCl}_6, \mathrm{SiO}_2$
2 $\mathrm{H}_4 \mathrm{SiO}_4, \mathrm{Si}$
3 $\mathrm{SiO}_2, \mathrm{Si}$
4 $\mathrm{H}_4 \mathrm{SiO}_4, \mathrm{SiO}_2$
Explanation:
$\mathrm{SiCl}_4$ on hydrolysis give $\mathrm{H}_2 \mathrm{SiO}_4$ $\mathrm{SiCl}_4+4 \mathrm{H}_2 \mathrm{O} \rightarrow \mathrm{H}_2 \mathrm{SiO}_3+4 \mathrm{HCl}$ $\mathrm{H}_4 \mathrm{SiO}_4$ loses the water at 1000 degree centigrade and produces $\mathrm{SiO}_2$ $\mathrm{H}_4 \mathrm{SiO}_4 \rightarrow \mathrm{SiO}_2+2 \mathrm{H}_2 \mathrm{O}$ So, $\mathrm{X}$ and $\mathrm{Y}$ are $\mathrm{H}_4 \mathrm{SiO}_4$ and $\mathrm{SiO}_2$ respectively.
AP EAMCET (Engg.)-2009
Ionic Equilibrium
229548
Which of the following does not form double salts?
1 $\mathrm{Li}_2 \mathrm{SO}_4$
2 $\mathrm{Na}_2 \mathrm{SO}_4$
3 $\mathrm{K}_2 \mathrm{SO}_4$
4 $\mathrm{Rb}_2 \mathrm{SO}_4$
Explanation:
Double salt is salt that contains more than one different contains or anion it completely dissociate into simple ions. Lithium is an electropositive element. It has vary small size. It cannot form double salt.
229539
How many compound given below are amphoteric oxides? $\mathrm{P}_2 \mathrm{O}_5, \mathrm{P}_4 \mathrm{O}_6, \mathrm{As}_2 \mathrm{O}_5, \mathrm{As}_4 \mathrm{O}_6, \mathrm{Sb}_2 \mathrm{O}_5, \mathrm{Sb}_4 \mathrm{O}_6, \mathrm{Bi}_2 \mathrm{O}_3$
1 2
2 3
3 4
4 6
Explanation:
The oxides of the type $\mathrm{E}_2 \mathrm{O}_3$ of $\mathrm{N}$ and $P$, $\mathrm{P}_2 \mathrm{O}_3\left(\mathrm{P}_4 \mathrm{O}_6\right.$, dimer of $\left.\mathrm{P}_2 \mathrm{O}_3\right)$ are purely acidic, that of $\mathrm{As}$ $\left(\mathrm{As}_4 \mathrm{O}_6\right.$, dimer of $\left.\mathrm{As}_2 \mathrm{O}_3\right)$ and $\mathrm{Sb}\left(\mathrm{Sb}_4 \mathrm{O}_6\right.$, dimer of $\left.\mathrm{Sb}_2 \mathrm{O}_3\right)$ amphoteric and that of $\mathrm{Bi}\left(\mathrm{Bi}_2 \mathrm{O}_3\right)$ is predominantly basic. The oxides of the type $\mathrm{E}_2 \mathrm{O}_3$ are more acidic, e.g. $\mathrm{N}_2 \mathrm{O}_3$, $\mathrm{P}_2 \mathrm{O}_5, \mathrm{As}_2 \mathrm{O}_5, \mathrm{Sb}_2 \mathrm{O}_5$ So, in the given set of oxides of group- 15 elements, two oxides are amphoteric, $\mathrm{As}_4 \mathrm{O}_6$ and $\mathrm{Sb}_4 \mathrm{O}_6$.
Shift-II
Ionic Equilibrium
229540
Which acid among the following has the highest $\mathrm{pK}_{\mathrm{a}}$ value ?
1 $\mathrm{HC} \ell$
2 $\mathrm{HF}$
3 $\mathrm{H} \ell$
4 $\mathrm{HBr}$
Explanation:
$\mathrm{HF}\left(\mathrm{pK}_{\mathrm{a}}=3.1\right.$ ) $\mathrm{HCl}\left(\mathrm{pK}_{\mathrm{a}}=-6.0\right)$ $\mathrm{HBr}\left(\mathrm{pK}_{\mathrm{a}}=-9.0\right)$ $\mathrm{HI}\left(\mathrm{pK}_{\mathrm{a}}=-9.5\right)$ Therefore, $\mathrm{HF}$ has highest $\mathrm{pK}_{\mathrm{a}}$ value. Hence, the correct option is (b).
Shift-I
Ionic Equilibrium
229546
Using the Lewis concept, which one of the following has the strongest acidic strength ?
1 $\mathrm{H}_3 \mathrm{PO}_4$
2 $\mathrm{H}_3 \mathrm{PO}_3$
3 $\mathrm{H}_3 \mathrm{PO}_2$
4 All are of equal strength
Explanation:
$\mathrm{H}_3 \mathrm{PO}_4$ has the strongest acid strength as the no. of $\mathrm{O}$ atom is more in case of $\mathrm{H}_3 \mathrm{PO}_4$. As the no. of $\mathrm{O}$ atom increases the strength of the acid increases. Oxygen is highly electronegative element, and so if there are more $\mathrm{O}$ atoms present, more will be the electron pulling tendency. So, $\mathrm{O}-\mathrm{H}$ bond weakening results more acidic character.
SCRA-2009
Ionic Equilibrium
229547
$\mathrm{SiCl}_4$ on hydrolysis forms ' $\mathrm{X}$ ' and $\mathrm{HCl}$, compound ' $\mathrm{X}$ ' losses water at $1000^{\circ} \mathrm{C}$ and gives ' $Y$ '. Compounds ' $X$ ' and ' $Y$ ' respectively are
1 $\mathrm{H}_2 \mathrm{SiCl}_6, \mathrm{SiO}_2$
2 $\mathrm{H}_4 \mathrm{SiO}_4, \mathrm{Si}$
3 $\mathrm{SiO}_2, \mathrm{Si}$
4 $\mathrm{H}_4 \mathrm{SiO}_4, \mathrm{SiO}_2$
Explanation:
$\mathrm{SiCl}_4$ on hydrolysis give $\mathrm{H}_2 \mathrm{SiO}_4$ $\mathrm{SiCl}_4+4 \mathrm{H}_2 \mathrm{O} \rightarrow \mathrm{H}_2 \mathrm{SiO}_3+4 \mathrm{HCl}$ $\mathrm{H}_4 \mathrm{SiO}_4$ loses the water at 1000 degree centigrade and produces $\mathrm{SiO}_2$ $\mathrm{H}_4 \mathrm{SiO}_4 \rightarrow \mathrm{SiO}_2+2 \mathrm{H}_2 \mathrm{O}$ So, $\mathrm{X}$ and $\mathrm{Y}$ are $\mathrm{H}_4 \mathrm{SiO}_4$ and $\mathrm{SiO}_2$ respectively.
AP EAMCET (Engg.)-2009
Ionic Equilibrium
229548
Which of the following does not form double salts?
1 $\mathrm{Li}_2 \mathrm{SO}_4$
2 $\mathrm{Na}_2 \mathrm{SO}_4$
3 $\mathrm{K}_2 \mathrm{SO}_4$
4 $\mathrm{Rb}_2 \mathrm{SO}_4$
Explanation:
Double salt is salt that contains more than one different contains or anion it completely dissociate into simple ions. Lithium is an electropositive element. It has vary small size. It cannot form double salt.