229351
The activation energy for a simple chemical reaction $A \rightarrow B$ is $E_a$ in forward direction. They activation energy for reverse reaction
1 is negative of $E_a$
2 is always less than $\mathrm{E}_{\mathrm{a}}$
3 can be less than or more than $E_a$
4 is always double of $\mathrm{E}_{\mathrm{a}}$
Explanation:
The activation energy of reverse reaction is less than or more than activation energy $\left(E_a\right)$ of forward reaction. $\because \quad \Delta \mathrm{H}=\left(\mathrm{E}_{\mathrm{a}}\right)_{\mathrm{F}}-\left(\mathrm{E}_{\mathrm{a}}\right)_{\mathrm{R}}$ Because it depends. upon the nature of reaction. If $\left(E_{\mathrm{a}}\right)_{\mathrm{F}}<\left(\mathrm{E}_{\mathrm{a}}\right)_{\mathrm{R}}$ reaction is exothermic or $\left(E_a\right)_{\mathrm{F}}>\left(\mathrm{E}_{\mathrm{a}}\right)_R$ reaction is endothermic
UPTU/UPSEE-2018]**
Ionic Equilibrium
229344
Find the correct statement about catalyst.
1 It changes the value of equilibrium constant $\mathrm{K}_{\mathrm{c}}$ or $\mathrm{K}_{\mathrm{p}}$.
2 It decreases the activation energy of a reaction.
3 It changes the enthalpy of a reaction.
4 It is not specific in its function.
Explanation:
A catalyst is a substance which increase the rate of reaction without itself undergoing any permanent chemical change. Catalyst provides an alternate reaction mechanism by reducing the activation energy between reactants and product. A catalyst does not alter Gibbs energy $(\Delta \mathrm{G})$.
SRM JEEE-2013
Ionic Equilibrium
229345
$20 \mathrm{ml}$ of $0.1 \mathrm{M}$ acetic acid is mixed with $50 \mathrm{~mL}$ of potassium acetate. $K_a$ of acetic acid $=1.8 \times$ $10^{-5}$ at $27^{\circ} \mathrm{C}$. Calculate concentration of potassium acetate if $\mathrm{pH}$ of the mixture is 4.8 .
1 $0.1 \mathrm{M}$
2 $0.04 \mathrm{M}$
3 $0.4 \mathrm{M}$
4 $0.02 \mathrm{M}$
Explanation:
Given that, $\mathrm{pH}=4.8, \mathrm{pK}_{\mathrm{a}}=1.8 \times 10^{-5}$ Let the concentration of potassium acetate is $\mathrm{x}$. According to Henderson's equation$\mathrm{pH}=\mathrm{pK}_{\mathrm{a}}+\log \frac{[\text { salt }]}{[\text { acid }]}$ or $\quad 4.8=-\log \left(1.8 \times 10^{-5}\right)+\log \frac{\mathrm{x} \times 50}{20 \times 0.1 \mathrm{M}}$ or $\quad 4.8=4.74+\log 25 \mathrm{x}$ $\log 25 \mathrm{x}=0.06$ $25 \mathrm{x}=1.148$ $\therefore \quad \mathrm{x}=0.045 \mathrm{M}$
VITEEE-2009
Ionic Equilibrium
229355
Aqueous solution of which of the following compound is the best conductor of electric current?
The aqueous solution of hydrochloric acid $(\mathrm{HCl})$ is the best conductor of electric current as it is a strong electrolyte and its completely dissociated into ions.
229351
The activation energy for a simple chemical reaction $A \rightarrow B$ is $E_a$ in forward direction. They activation energy for reverse reaction
1 is negative of $E_a$
2 is always less than $\mathrm{E}_{\mathrm{a}}$
3 can be less than or more than $E_a$
4 is always double of $\mathrm{E}_{\mathrm{a}}$
Explanation:
The activation energy of reverse reaction is less than or more than activation energy $\left(E_a\right)$ of forward reaction. $\because \quad \Delta \mathrm{H}=\left(\mathrm{E}_{\mathrm{a}}\right)_{\mathrm{F}}-\left(\mathrm{E}_{\mathrm{a}}\right)_{\mathrm{R}}$ Because it depends. upon the nature of reaction. If $\left(E_{\mathrm{a}}\right)_{\mathrm{F}}<\left(\mathrm{E}_{\mathrm{a}}\right)_{\mathrm{R}}$ reaction is exothermic or $\left(E_a\right)_{\mathrm{F}}>\left(\mathrm{E}_{\mathrm{a}}\right)_R$ reaction is endothermic
UPTU/UPSEE-2018]**
Ionic Equilibrium
229344
Find the correct statement about catalyst.
1 It changes the value of equilibrium constant $\mathrm{K}_{\mathrm{c}}$ or $\mathrm{K}_{\mathrm{p}}$.
2 It decreases the activation energy of a reaction.
3 It changes the enthalpy of a reaction.
4 It is not specific in its function.
Explanation:
A catalyst is a substance which increase the rate of reaction without itself undergoing any permanent chemical change. Catalyst provides an alternate reaction mechanism by reducing the activation energy between reactants and product. A catalyst does not alter Gibbs energy $(\Delta \mathrm{G})$.
SRM JEEE-2013
Ionic Equilibrium
229345
$20 \mathrm{ml}$ of $0.1 \mathrm{M}$ acetic acid is mixed with $50 \mathrm{~mL}$ of potassium acetate. $K_a$ of acetic acid $=1.8 \times$ $10^{-5}$ at $27^{\circ} \mathrm{C}$. Calculate concentration of potassium acetate if $\mathrm{pH}$ of the mixture is 4.8 .
1 $0.1 \mathrm{M}$
2 $0.04 \mathrm{M}$
3 $0.4 \mathrm{M}$
4 $0.02 \mathrm{M}$
Explanation:
Given that, $\mathrm{pH}=4.8, \mathrm{pK}_{\mathrm{a}}=1.8 \times 10^{-5}$ Let the concentration of potassium acetate is $\mathrm{x}$. According to Henderson's equation$\mathrm{pH}=\mathrm{pK}_{\mathrm{a}}+\log \frac{[\text { salt }]}{[\text { acid }]}$ or $\quad 4.8=-\log \left(1.8 \times 10^{-5}\right)+\log \frac{\mathrm{x} \times 50}{20 \times 0.1 \mathrm{M}}$ or $\quad 4.8=4.74+\log 25 \mathrm{x}$ $\log 25 \mathrm{x}=0.06$ $25 \mathrm{x}=1.148$ $\therefore \quad \mathrm{x}=0.045 \mathrm{M}$
VITEEE-2009
Ionic Equilibrium
229355
Aqueous solution of which of the following compound is the best conductor of electric current?
The aqueous solution of hydrochloric acid $(\mathrm{HCl})$ is the best conductor of electric current as it is a strong electrolyte and its completely dissociated into ions.
229351
The activation energy for a simple chemical reaction $A \rightarrow B$ is $E_a$ in forward direction. They activation energy for reverse reaction
1 is negative of $E_a$
2 is always less than $\mathrm{E}_{\mathrm{a}}$
3 can be less than or more than $E_a$
4 is always double of $\mathrm{E}_{\mathrm{a}}$
Explanation:
The activation energy of reverse reaction is less than or more than activation energy $\left(E_a\right)$ of forward reaction. $\because \quad \Delta \mathrm{H}=\left(\mathrm{E}_{\mathrm{a}}\right)_{\mathrm{F}}-\left(\mathrm{E}_{\mathrm{a}}\right)_{\mathrm{R}}$ Because it depends. upon the nature of reaction. If $\left(E_{\mathrm{a}}\right)_{\mathrm{F}}<\left(\mathrm{E}_{\mathrm{a}}\right)_{\mathrm{R}}$ reaction is exothermic or $\left(E_a\right)_{\mathrm{F}}>\left(\mathrm{E}_{\mathrm{a}}\right)_R$ reaction is endothermic
UPTU/UPSEE-2018]**
Ionic Equilibrium
229344
Find the correct statement about catalyst.
1 It changes the value of equilibrium constant $\mathrm{K}_{\mathrm{c}}$ or $\mathrm{K}_{\mathrm{p}}$.
2 It decreases the activation energy of a reaction.
3 It changes the enthalpy of a reaction.
4 It is not specific in its function.
Explanation:
A catalyst is a substance which increase the rate of reaction without itself undergoing any permanent chemical change. Catalyst provides an alternate reaction mechanism by reducing the activation energy between reactants and product. A catalyst does not alter Gibbs energy $(\Delta \mathrm{G})$.
SRM JEEE-2013
Ionic Equilibrium
229345
$20 \mathrm{ml}$ of $0.1 \mathrm{M}$ acetic acid is mixed with $50 \mathrm{~mL}$ of potassium acetate. $K_a$ of acetic acid $=1.8 \times$ $10^{-5}$ at $27^{\circ} \mathrm{C}$. Calculate concentration of potassium acetate if $\mathrm{pH}$ of the mixture is 4.8 .
1 $0.1 \mathrm{M}$
2 $0.04 \mathrm{M}$
3 $0.4 \mathrm{M}$
4 $0.02 \mathrm{M}$
Explanation:
Given that, $\mathrm{pH}=4.8, \mathrm{pK}_{\mathrm{a}}=1.8 \times 10^{-5}$ Let the concentration of potassium acetate is $\mathrm{x}$. According to Henderson's equation$\mathrm{pH}=\mathrm{pK}_{\mathrm{a}}+\log \frac{[\text { salt }]}{[\text { acid }]}$ or $\quad 4.8=-\log \left(1.8 \times 10^{-5}\right)+\log \frac{\mathrm{x} \times 50}{20 \times 0.1 \mathrm{M}}$ or $\quad 4.8=4.74+\log 25 \mathrm{x}$ $\log 25 \mathrm{x}=0.06$ $25 \mathrm{x}=1.148$ $\therefore \quad \mathrm{x}=0.045 \mathrm{M}$
VITEEE-2009
Ionic Equilibrium
229355
Aqueous solution of which of the following compound is the best conductor of electric current?
The aqueous solution of hydrochloric acid $(\mathrm{HCl})$ is the best conductor of electric current as it is a strong electrolyte and its completely dissociated into ions.
229351
The activation energy for a simple chemical reaction $A \rightarrow B$ is $E_a$ in forward direction. They activation energy for reverse reaction
1 is negative of $E_a$
2 is always less than $\mathrm{E}_{\mathrm{a}}$
3 can be less than or more than $E_a$
4 is always double of $\mathrm{E}_{\mathrm{a}}$
Explanation:
The activation energy of reverse reaction is less than or more than activation energy $\left(E_a\right)$ of forward reaction. $\because \quad \Delta \mathrm{H}=\left(\mathrm{E}_{\mathrm{a}}\right)_{\mathrm{F}}-\left(\mathrm{E}_{\mathrm{a}}\right)_{\mathrm{R}}$ Because it depends. upon the nature of reaction. If $\left(E_{\mathrm{a}}\right)_{\mathrm{F}}<\left(\mathrm{E}_{\mathrm{a}}\right)_{\mathrm{R}}$ reaction is exothermic or $\left(E_a\right)_{\mathrm{F}}>\left(\mathrm{E}_{\mathrm{a}}\right)_R$ reaction is endothermic
UPTU/UPSEE-2018]**
Ionic Equilibrium
229344
Find the correct statement about catalyst.
1 It changes the value of equilibrium constant $\mathrm{K}_{\mathrm{c}}$ or $\mathrm{K}_{\mathrm{p}}$.
2 It decreases the activation energy of a reaction.
3 It changes the enthalpy of a reaction.
4 It is not specific in its function.
Explanation:
A catalyst is a substance which increase the rate of reaction without itself undergoing any permanent chemical change. Catalyst provides an alternate reaction mechanism by reducing the activation energy between reactants and product. A catalyst does not alter Gibbs energy $(\Delta \mathrm{G})$.
SRM JEEE-2013
Ionic Equilibrium
229345
$20 \mathrm{ml}$ of $0.1 \mathrm{M}$ acetic acid is mixed with $50 \mathrm{~mL}$ of potassium acetate. $K_a$ of acetic acid $=1.8 \times$ $10^{-5}$ at $27^{\circ} \mathrm{C}$. Calculate concentration of potassium acetate if $\mathrm{pH}$ of the mixture is 4.8 .
1 $0.1 \mathrm{M}$
2 $0.04 \mathrm{M}$
3 $0.4 \mathrm{M}$
4 $0.02 \mathrm{M}$
Explanation:
Given that, $\mathrm{pH}=4.8, \mathrm{pK}_{\mathrm{a}}=1.8 \times 10^{-5}$ Let the concentration of potassium acetate is $\mathrm{x}$. According to Henderson's equation$\mathrm{pH}=\mathrm{pK}_{\mathrm{a}}+\log \frac{[\text { salt }]}{[\text { acid }]}$ or $\quad 4.8=-\log \left(1.8 \times 10^{-5}\right)+\log \frac{\mathrm{x} \times 50}{20 \times 0.1 \mathrm{M}}$ or $\quad 4.8=4.74+\log 25 \mathrm{x}$ $\log 25 \mathrm{x}=0.06$ $25 \mathrm{x}=1.148$ $\therefore \quad \mathrm{x}=0.045 \mathrm{M}$
VITEEE-2009
Ionic Equilibrium
229355
Aqueous solution of which of the following compound is the best conductor of electric current?
The aqueous solution of hydrochloric acid $(\mathrm{HCl})$ is the best conductor of electric current as it is a strong electrolyte and its completely dissociated into ions.
