229556
The dissociation constant of a weak acid is $1 \times 10^{-4}$. In order to prepare a buffer solution with a $\mathrm{pH}=5$, the [Salt] $]$ [Acid] ratio should be
1 $4: 5$
2 $10: 1$
3 $5: 4$
4 $1: 10$
Explanation:
$\mathrm{pH}=\mathrm{pK}_{\mathrm{a}}+\log \frac{[\text { Salt }]}{[\text { Acid }]}$ $\mathrm{K}_{\mathrm{a}}=1 \times 10^{-4}$ $\left[\because \mathrm{pK}_{\mathrm{a}}=-\log \mathrm{K}_{\mathrm{a}}\right]$ $=-20 \mathrm{~g}\left(1 \times 10^{-4}\right)$ $=4$ From equation (i)- $5=-\log \mathrm{K}_{\mathrm{a}}+\log \frac{[\text { Salt }]}{[\text { Acid }]}$ $5=4+\log \frac{[\text { Salt }]}{[\text { Acid }]}$ $5-4=\log \frac{[\text { Salt }]}{[\text { Acid }]}$ $1=\log \frac{[\text { Salt }]}{[\text { Acid }]}$ $\frac{[\text { Salt }]}{[\text { Acid }]}=10=10: 1$
Karnataka NEET-2013
Ionic Equilibrium
229558
Identify Bronsted-Lowry acids in the reaction given. The correct answer is
1 (A), (C)
2 (B), (D)
3 (A), (D)
4 (B), (C)
Explanation:
The given reversible reaction is: A base after gaining a proton $\left(\mathrm{H}^{+}\right)$gives conjugate acid. Hence, in the above reaction $\mathrm{A}$ and $\mathrm{D}$ are the acids.
2008
Ionic Equilibrium
229562
Which compound having maximum value of $\mathrm{pK}_{\mathrm{a}}$ from following?
Exp: Phenol $\left(\mathrm{C}_6 \mathrm{H}_5 \mathrm{OH}\right)$ has the maximum value of $\mathrm{pK}_{\mathrm{a}}$ from the following. The $\mathrm{pK}_{\mathrm{a}}$ value is inversely proportional to the acidity of compound. Phenol is least acidic in nature because it has the more $\mathrm{pK}_{\mathrm{a}}$ value. The $\mathrm{pK}_{\mathrm{a}}$ order is- Phenol $>$ m-nitrophenol $>$ p-nitrophenol $>0$ onitrophenol.
GUJCET-2021
Ionic Equilibrium
229563
Match the following | Column-I (Acid) | Column-II (pKa value) | |---------------------------------------------|------------------------| |
229556
The dissociation constant of a weak acid is $1 \times 10^{-4}$. In order to prepare a buffer solution with a $\mathrm{pH}=5$, the [Salt] $]$ [Acid] ratio should be
1 $4: 5$
2 $10: 1$
3 $5: 4$
4 $1: 10$
Explanation:
$\mathrm{pH}=\mathrm{pK}_{\mathrm{a}}+\log \frac{[\text { Salt }]}{[\text { Acid }]}$ $\mathrm{K}_{\mathrm{a}}=1 \times 10^{-4}$ $\left[\because \mathrm{pK}_{\mathrm{a}}=-\log \mathrm{K}_{\mathrm{a}}\right]$ $=-20 \mathrm{~g}\left(1 \times 10^{-4}\right)$ $=4$ From equation (i)- $5=-\log \mathrm{K}_{\mathrm{a}}+\log \frac{[\text { Salt }]}{[\text { Acid }]}$ $5=4+\log \frac{[\text { Salt }]}{[\text { Acid }]}$ $5-4=\log \frac{[\text { Salt }]}{[\text { Acid }]}$ $1=\log \frac{[\text { Salt }]}{[\text { Acid }]}$ $\frac{[\text { Salt }]}{[\text { Acid }]}=10=10: 1$
Karnataka NEET-2013
Ionic Equilibrium
229558
Identify Bronsted-Lowry acids in the reaction given. The correct answer is
1 (A), (C)
2 (B), (D)
3 (A), (D)
4 (B), (C)
Explanation:
The given reversible reaction is: A base after gaining a proton $\left(\mathrm{H}^{+}\right)$gives conjugate acid. Hence, in the above reaction $\mathrm{A}$ and $\mathrm{D}$ are the acids.
2008
Ionic Equilibrium
229562
Which compound having maximum value of $\mathrm{pK}_{\mathrm{a}}$ from following?
Exp: Phenol $\left(\mathrm{C}_6 \mathrm{H}_5 \mathrm{OH}\right)$ has the maximum value of $\mathrm{pK}_{\mathrm{a}}$ from the following. The $\mathrm{pK}_{\mathrm{a}}$ value is inversely proportional to the acidity of compound. Phenol is least acidic in nature because it has the more $\mathrm{pK}_{\mathrm{a}}$ value. The $\mathrm{pK}_{\mathrm{a}}$ order is- Phenol $>$ m-nitrophenol $>$ p-nitrophenol $>0$ onitrophenol.
GUJCET-2021
Ionic Equilibrium
229563
Match the following | Column-I (Acid) | Column-II (pKa value) | |---------------------------------------------|------------------------| |
229556
The dissociation constant of a weak acid is $1 \times 10^{-4}$. In order to prepare a buffer solution with a $\mathrm{pH}=5$, the [Salt] $]$ [Acid] ratio should be
1 $4: 5$
2 $10: 1$
3 $5: 4$
4 $1: 10$
Explanation:
$\mathrm{pH}=\mathrm{pK}_{\mathrm{a}}+\log \frac{[\text { Salt }]}{[\text { Acid }]}$ $\mathrm{K}_{\mathrm{a}}=1 \times 10^{-4}$ $\left[\because \mathrm{pK}_{\mathrm{a}}=-\log \mathrm{K}_{\mathrm{a}}\right]$ $=-20 \mathrm{~g}\left(1 \times 10^{-4}\right)$ $=4$ From equation (i)- $5=-\log \mathrm{K}_{\mathrm{a}}+\log \frac{[\text { Salt }]}{[\text { Acid }]}$ $5=4+\log \frac{[\text { Salt }]}{[\text { Acid }]}$ $5-4=\log \frac{[\text { Salt }]}{[\text { Acid }]}$ $1=\log \frac{[\text { Salt }]}{[\text { Acid }]}$ $\frac{[\text { Salt }]}{[\text { Acid }]}=10=10: 1$
Karnataka NEET-2013
Ionic Equilibrium
229558
Identify Bronsted-Lowry acids in the reaction given. The correct answer is
1 (A), (C)
2 (B), (D)
3 (A), (D)
4 (B), (C)
Explanation:
The given reversible reaction is: A base after gaining a proton $\left(\mathrm{H}^{+}\right)$gives conjugate acid. Hence, in the above reaction $\mathrm{A}$ and $\mathrm{D}$ are the acids.
2008
Ionic Equilibrium
229562
Which compound having maximum value of $\mathrm{pK}_{\mathrm{a}}$ from following?
Exp: Phenol $\left(\mathrm{C}_6 \mathrm{H}_5 \mathrm{OH}\right)$ has the maximum value of $\mathrm{pK}_{\mathrm{a}}$ from the following. The $\mathrm{pK}_{\mathrm{a}}$ value is inversely proportional to the acidity of compound. Phenol is least acidic in nature because it has the more $\mathrm{pK}_{\mathrm{a}}$ value. The $\mathrm{pK}_{\mathrm{a}}$ order is- Phenol $>$ m-nitrophenol $>$ p-nitrophenol $>0$ onitrophenol.
GUJCET-2021
Ionic Equilibrium
229563
Match the following | Column-I (Acid) | Column-II (pKa value) | |---------------------------------------------|------------------------| |
229556
The dissociation constant of a weak acid is $1 \times 10^{-4}$. In order to prepare a buffer solution with a $\mathrm{pH}=5$, the [Salt] $]$ [Acid] ratio should be
1 $4: 5$
2 $10: 1$
3 $5: 4$
4 $1: 10$
Explanation:
$\mathrm{pH}=\mathrm{pK}_{\mathrm{a}}+\log \frac{[\text { Salt }]}{[\text { Acid }]}$ $\mathrm{K}_{\mathrm{a}}=1 \times 10^{-4}$ $\left[\because \mathrm{pK}_{\mathrm{a}}=-\log \mathrm{K}_{\mathrm{a}}\right]$ $=-20 \mathrm{~g}\left(1 \times 10^{-4}\right)$ $=4$ From equation (i)- $5=-\log \mathrm{K}_{\mathrm{a}}+\log \frac{[\text { Salt }]}{[\text { Acid }]}$ $5=4+\log \frac{[\text { Salt }]}{[\text { Acid }]}$ $5-4=\log \frac{[\text { Salt }]}{[\text { Acid }]}$ $1=\log \frac{[\text { Salt }]}{[\text { Acid }]}$ $\frac{[\text { Salt }]}{[\text { Acid }]}=10=10: 1$
Karnataka NEET-2013
Ionic Equilibrium
229558
Identify Bronsted-Lowry acids in the reaction given. The correct answer is
1 (A), (C)
2 (B), (D)
3 (A), (D)
4 (B), (C)
Explanation:
The given reversible reaction is: A base after gaining a proton $\left(\mathrm{H}^{+}\right)$gives conjugate acid. Hence, in the above reaction $\mathrm{A}$ and $\mathrm{D}$ are the acids.
2008
Ionic Equilibrium
229562
Which compound having maximum value of $\mathrm{pK}_{\mathrm{a}}$ from following?
Exp: Phenol $\left(\mathrm{C}_6 \mathrm{H}_5 \mathrm{OH}\right)$ has the maximum value of $\mathrm{pK}_{\mathrm{a}}$ from the following. The $\mathrm{pK}_{\mathrm{a}}$ value is inversely proportional to the acidity of compound. Phenol is least acidic in nature because it has the more $\mathrm{pK}_{\mathrm{a}}$ value. The $\mathrm{pK}_{\mathrm{a}}$ order is- Phenol $>$ m-nitrophenol $>$ p-nitrophenol $>0$ onitrophenol.
GUJCET-2021
Ionic Equilibrium
229563
Match the following | Column-I (Acid) | Column-II (pKa value) | |---------------------------------------------|------------------------| |
229556
The dissociation constant of a weak acid is $1 \times 10^{-4}$. In order to prepare a buffer solution with a $\mathrm{pH}=5$, the [Salt] $]$ [Acid] ratio should be
1 $4: 5$
2 $10: 1$
3 $5: 4$
4 $1: 10$
Explanation:
$\mathrm{pH}=\mathrm{pK}_{\mathrm{a}}+\log \frac{[\text { Salt }]}{[\text { Acid }]}$ $\mathrm{K}_{\mathrm{a}}=1 \times 10^{-4}$ $\left[\because \mathrm{pK}_{\mathrm{a}}=-\log \mathrm{K}_{\mathrm{a}}\right]$ $=-20 \mathrm{~g}\left(1 \times 10^{-4}\right)$ $=4$ From equation (i)- $5=-\log \mathrm{K}_{\mathrm{a}}+\log \frac{[\text { Salt }]}{[\text { Acid }]}$ $5=4+\log \frac{[\text { Salt }]}{[\text { Acid }]}$ $5-4=\log \frac{[\text { Salt }]}{[\text { Acid }]}$ $1=\log \frac{[\text { Salt }]}{[\text { Acid }]}$ $\frac{[\text { Salt }]}{[\text { Acid }]}=10=10: 1$
Karnataka NEET-2013
Ionic Equilibrium
229558
Identify Bronsted-Lowry acids in the reaction given. The correct answer is
1 (A), (C)
2 (B), (D)
3 (A), (D)
4 (B), (C)
Explanation:
The given reversible reaction is: A base after gaining a proton $\left(\mathrm{H}^{+}\right)$gives conjugate acid. Hence, in the above reaction $\mathrm{A}$ and $\mathrm{D}$ are the acids.
2008
Ionic Equilibrium
229562
Which compound having maximum value of $\mathrm{pK}_{\mathrm{a}}$ from following?
Exp: Phenol $\left(\mathrm{C}_6 \mathrm{H}_5 \mathrm{OH}\right)$ has the maximum value of $\mathrm{pK}_{\mathrm{a}}$ from the following. The $\mathrm{pK}_{\mathrm{a}}$ value is inversely proportional to the acidity of compound. Phenol is least acidic in nature because it has the more $\mathrm{pK}_{\mathrm{a}}$ value. The $\mathrm{pK}_{\mathrm{a}}$ order is- Phenol $>$ m-nitrophenol $>$ p-nitrophenol $>0$ onitrophenol.
GUJCET-2021
Ionic Equilibrium
229563
Match the following | Column-I (Acid) | Column-II (pKa value) | |---------------------------------------------|------------------------| |
