Introduction to Oxidation and Reduction

Q.

Write the complete balanced reaction (a) Potassium bromide(aq) + Barium iodide(aq) → Potassium iodide(aq) + Barium bromide(s)

Q.

What happens when Magnesium burns in air? Write a balanced equation.

Q.

What does the given reaction indicate? $\mathrm{Cu}+2{\mathrm{AgNO}}_3\to \mathrm{Cu}{\left({\mathrm{NO}}_3\right)}_2+2\mathrm{Ag}$

Q. 1 molal aqueous solution of an electrolyte $A_2{B}_3$ is 60% ionised . The boiling point of the solution at 1 atm in K is ( Rounded -off to the nearest integer ) $[K_{b}for\left(H_{2}O\right)=0.53KKgmo{l}^{-1}]$
(JEE MAIN 2021)

Q. The indicator used in the titration of iodine against sodium thiosulphate is:

1. Starch
2. $K_{3}Fe(CN{)}_6$
3. $K_{2}Cr{O}_4$
4. Potassium

Q. Oxidation number of cobalt in $\left[Co\right(N{H}_3{)}_6]C{l}_{2}Br$ is -

1. 6
2. 3
3. zero
4. 2

Q.

“Oxidation and reduction process occurs simultaneously”. Justify the statement with the help of an example.

Q.

${\mathrm{H}}_2{\mathrm{O}}_2$ is: ?

1. an oxidising agent

2. a reducing agent

3. both oxidising and reducing agent

4. None of these

Q. The percentage of free $S{O}_3$ in an oleum is $60\%$. The given sample in terms of $\%H_{2}S{O}_4$ can be labelled as :

1. $160\%$
2. $140\%$
3. $113.5\%$
4. $104.5\%$

Q. The volume strength of $8.9M{H}_2{O}_2$ solution calculated at $273K$ and $1atm$ is _____. ( $R=0.0821Latm{K}^{–1}mo{l}^{–1}$) (rounded off to the nearest integer)

Q.

Which of the following is not an example of redox reaction?
(a) $CuO+H_2\to Cu+H_{2}O$
(b) $F{e}_2{O}_3+3CO\to 2Fe+3C{O}_2$
(c) $2K+F_2\to 2KF$
(d) $BaC{l}_2+H_{2}S{O}_4\to BaS{O}_4+2HCl$

Q.

The percentage of available chlorine in a pure bleaching powder $\left(\mathrm{Ca}{\left(\mathrm{OCl}\right)}_2\right)$ sample is ______

Q. Which of the following is not oxidation?

1. Removal of Hydrogen
2. Addition of Electronegative element
   
3. Removal of Electropositive element
   
4. Addition of Electropositive element

Q.

What is a redox reaction with an example?

Q.

The reaction $4{\mathrm{NH}}_3+5{\mathrm{O}}_2\to 4\mathrm{NO}+6{\mathrm{H}}_2\mathrm{O}$ is an example of I. Combination II. Displacement III. Redox IV, Neutralisation.

1. I and II

2. I and III

3. II and III

4. I and IV

Q. $K_{2}Mn{O}_4$ in acidic or neutral medium undergo disproportionation reaction to give

1. $Mn{O}_4^{-}$
2. $Mn{O}_2$
3. $Mn{O}_4^{2-}$
4. $M{n}_2{O}_4^{2-}$

Q.

When an oxide of a non-metal reacts with water, which of the following is formed?

1. Acid

2. Base

3. Salt

4. None of these

Q. $4.5g$ water is added into an oleum sample labelled as $109\%H_{2}S{O}_4.$ What is the amount of free $S{O}_3$ remaining in the solution?

1. $10g$
2. $12g$
3. $20g$
4. $24g$

Q.

A sample of $AgCl$ was treated with $500mL$ of $1.5M$ $N{a}_{2}C{O}_3$ solution to give $A{g}_{2}C{O}_3$. The remaining solution contained $0.0026g$ of $C{l}^{-}$ per litre. The solubility product of $AgCl$ is if $K_{sp}\left(A{g}_{2}C{O}_3\right)=8.2\times {10}^{-12}$

1. 

2. 

3. 

4. 

Q.

Name the process of conversion of ${\mathrm{K}}_2{\mathrm{Cr}}_2{\mathrm{O}}_7$ into $C{r}_2{\left(S{O}_4\right)}_3$.

Q. What is the $\%$ of free $S{O}_3$ in an oleum that is labelled as $104.5\%H_{2}S{O}_4$ ?

1. 10
2. 20
3. 40
4. 50

Q. When $KMn{O}_4$ is reduced with oxalic acid in acidic solution, the change in oxidation number of $Mn$ is

Q.

Dichromate ion is treated with base, the oxidation number of $\mathrm{Cr}$ in the product formed in the following reaction is:

${\mathrm{Cr}}_2{\mathrm{O}}_7^{-2}+2{\mathrm{OH}}^{-}\rightleftharpoons 2{\mathrm{CrO}}_4^{-2}+{\mathrm{H}}_2\mathrm{O}$

Q. When $N{a}_2{S}_2{O}_3$ reacts with $I_2$ to form $N{a}_2{S}_4{O}_6$ and $NaI$ then which statement(s) is correct?

1. n-factor for $N{a}_2{S}_2{O}_3$ is one
2. n-factor for $I_2$ is two
3. 2 moles of $N{a}_2{S}_2{O}_3$ is reacted with 1 mole of $I_2$
4. n-factor for $N{a}_2{S}_4{O}_6$ is one

Q. In an aqueous solution of barium nitrate, the $\left[N{O}_3^{-}\right]$ is 0.080 M. This solution can be labeled as

1. $0.040N\left(Ba\right(N{O}_2{)}_2$
2. $0.160MBa(N{O}_3{)}_2$
3. $0.080NBa(N{O}_3{)}_2$
4. $0.080MN{O}_3^{-}$

Q. On heating, a sample of $NaCl{O}_3$, it gets converted to $NaCl$ with a loss of 0.16 g of oxygen. The residue is dissolved in water and precipitated as $AgCl$. The mass of $AgCl$ (in g) obtained will be :
(Given molar mass of $AgCl=143.5gmo{l}^{-1}$)

1. $0.35$
2. $0.54$
3. $0.41$
4. $0.48$

Q. $2NHCl$ solution will have the same molar concentration as:

1. $4.0N{H}_{2}S{O}_4$
2. $0.5N{H}_{2}S{O}_4$
3. $1N{H}_{2}S{O}_4$
4. $2N{H}_{2}S{O}_4$

Q.

Explain by giving one example why do oxidation and reduction proceed side by side ?

Q.

Calculate the percentage of iron in K₃Fe(CN)₆ (K = 39, Fe = 56, C = 12, N = 14).

Q.

For a redox reaction to proceed in a cell, the e.m.f. must be:

1. Fixed

2. Zero

3. Positive

4. Negative