Redox Reactions and Couple

Q.

What is the relation between electrochemical cell and Gibbs free energy of the cell reaction?

Q.

What is the n factor of ${\mathrm{KMNO}}_4$ in basic medium?

Q. $KMn{O}_4$ acts as an oxidising agent in the neutral medium and gets reduced to $Mn{O}_2$.The equivalent weight of $KMn{O}_4$ in neutral medium

1. mol. wt/2
2. mol. wt/3
3. mol. wt/4
4. mol .wt/7

Q. Calculate the emf of the concentration cell at $298K$.
$Pt\left(s\right)|H_2(g,p_1)|HCl\left(aq\right)|H_2(g,p_2)|Pt\left(s\right)$

$p_1=600torr{p}_2=400torr$

Take:
$log\frac{3}{2}=0.176$

1. $1.02V$
2. $0.15V$
3. $0.005V$
4. $0.025V$

Q. What is the oxidation state of cu and fe in cufes2

Q. The emf of a cell corresponding to the reaction $Zn\text{(s)}+2H^{+}\text{(aq)}\to Z{n}^{2+}\left(0.1\text{M}\right)+H_2(\text{g},1\text{bar})$ is $0.28\text{V}$ at ${25}^{\circ }\text{C}$. Calculate the pH of the solution at the hydrogen electrode. Given $E_{Z{n}^{2+}|Zn}^{\circ }=-0.763\text{V}$

1. $8.67$
2. $6$
3. $7.20$
4. $10.35$

Q.

Which chemical is used in the battery?

Q.

The tailing of mercury on exposure to air shows a change in oxidation state by one.

1. True
2. False

Q. Identify the species undergoing oxidation and reduction:
2Na(s) + H2(g)---- 2NaH(s)

Q.

Electrode potential of hydrogen electrode is18mV then concentration of H+ is

Q. A mixture of boron trichloride and hydrogen is subjected to silent electric discharge to form ‘A’ and HCl. ‘A’ is mixed with $N{H}_3$ and heated to ${200}^{\circ }C$ to form ‘B’. The formula of ‘B’ is

1. 
2. 
3. 
4. 

Q. $Pt|H_2(g,P_1)|HCl\left(0.1M\right)|H_2(g,P_2)|Pt$

A concentration cell is formed by two hydrogen electrodes having hydrogen gas at different pressures $P_1\&P_2$, dipped in the same electrolytic solution $\left(0.1MHCl\right)$ at $298K$.
Choose the correct option :

1. $E_{cell}^0>0$
2. $E_{cell}^0<0$
3. For spontaneous reaction to take place,
   $P_1>P_2$
4. Higher the concentration of electrolyte, more is the EMF generated.

Q.

What is electrochemical cell?

Q.

On electrolysis of fused $NaH$, hydrogen gas is produced at which electrode?

Q.

Define the following term:

Oxidation

Q. ntGiven electrode potentials:n ntFe3+ plus e ---------Fe2+ ; Eo=0.771n ntI2+2e ----------------2I- ; Eo =0.536n ntEo cell for the cell reactionn nt2Fe3+ plus 2I- ----------2Fe2+ plus I2 is -n nt1. (2x0.771-0.536) =1.006 voltsn nt2. (0.771-0.5x0.536)=0.503 voltsn nt3. 0.771-0.536=0.253 voltsn nt4. 0.536-0.771=-0.235 voltsn

Q.

What is an electrochemical reaction?

Q. EMF of the following cell is $0.634volt$ at $298K$ $Pt|H_2\left(1atm\right)|H^{+}\left(aq\right)||H{g}_2^{2+}(aq.1N)|Hg\left(l\right)$. The pH of anode compartment is :

(Given, $E_{H{g}_2^{2+}|Hg}^o=0.28\text{and}\frac{2.303RT}{F}=0.059$)

Q.

An --------------- cell is a device in which electrical energy is converted into chemical energy and vice versa.

Q. What is the oxidation state of Mn in Manganese (VII) oxide?

1. 7
2. 5
3. 3
4. 1

Q. Which of the following oxidation states are the most characteristic for lead and tin respectively :

1. +2, +4
2. +4, +4
3. +2, +2
4. +4, +2

Q. $Zn\left(s\right)+2AgN{O}_3\left(aq\right)\to Zn\left(N{O}_3{)}_2\right(aq)+2Ag(s)$
Write the chemical equation for oxidation and reduction.

Q. The redox reaction among the following is:

1. formation of ozone from atmospheric oxygen in the presence of sunlight
2. reaction of $\left[Co\right(H_{2}O{)}_6]C{l}_3$ with $AgN{O}_3$
3. reaction of $H_{2}S{O}_4$ with $NaOH$
4. combination of dinitrogen with dioxygen at $2000K$

Q.

What is an electrolytic cell?

Q.

is the terminals of galvanic cell is just opposite in electrolytic cell and why

Q.

Mark the false statement

[MP PET 1997]

1. A salt bridge is used to eliminate liquid junction potential
2. Nernst equation for single electrode potential is
3. The Gibbs free energy change, is related with electromotive force (E) , as
4. The efficiency of a hydrogen oxygen fuel cell is 23%

Q.

In a cell representation, the oxidation half reaction is written:

1. On the left hand side

2. As arrows

3. On the right hand side

4. As charges

Q. Oxidation state of O in $O{F}_2$ Is

1. -2
2. 1
3. 2
4. -1

Q. What is the oxidation state of Mn in Manganese (VII) oxide?

1. 1
2. 5
3. 3
4. 7

Q. Find the n-factor in the following chemical changes.
$KMn{O}_4\stackrel{O{H}^{-}\left(concentratedbasicmedium\right)}{\to }M{n}^{6+}$