Redox Reactions - Physical Chemistry PYQ

For the redox reaction

\(\mathrm{MnO}_4^{-}+\mathrm{C}_2 \mathrm{O}_4^{2-}+\mathrm{H}^{+} \longrightarrow \mathrm{Mn}^{2+}+\mathrm{CO}_2+\mathrm{H}_2 \mathrm{O}\),

the correct coefficients of the reactants for the balanced reaction are respectively

Assertion (A) The colour of old lead paintings can be restored by washing them with a dilute solution of \(\mathrm{H}_2 \mathrm{O}_2\).

Reason (R) Hydrogen peroxide reduces \(\mathrm{PbS}\) to \(\mathrm{Pb}\).

Which among the following species acts as a self-indicator?

Which of the following statement is incorrect?

Which among the following species does not show disproportionation reaction?

How many grams of Mg is required to completely reduce \(100 \mathrm{~mL}, 0.1 \mathrm{~M} \mathrm{~NO}_3^{-}\) solution using the following reaction?

$$\mathrm{NO}_3^{-}+\mathrm{Mg} \longrightarrow \mathrm{Mg}^{2+}+\mathrm{NH}_3$$

What is the oxidation state of S in the sulphur containing product of the following reaction?

$$\mathrm{SO}_3^{2-}(a q)+\mathrm{Br}_2(l)+\mathrm{H}_2 \mathrm{O} \longrightarrow$$

In the reaction of phosphorus with conc. \(\mathrm{HNO}_3\), the oxidised and reduced products respectively are

What are the oxidation states of three Br atoms in \(\mathrm{Br}_3 \mathrm{O}_8\) molecule?

What are the oxidation numbers of S atoms in \(\mathrm{S}_4 \mathrm{O}_6^{2-}\) ?

Given below are two statements.

Statement I : In the decomposition of potassium chlorate Cl is reduced.

Statement II : Reaction of Na with $\mathrm{O}_2$ to form $\mathrm{Na}_2 \mathrm{O}$ is a redox reaction.

The correct answer is

Observe the following reactions

(i) $2 \mathrm{KClO}_3(s) \xrightarrow{\Delta} 2 \mathrm{KCl}(s)+3 \mathrm{O}_2(g)$

(ii) $2 \mathrm{H}_2 \mathrm{O}_2(a q) \xrightarrow{\Delta} 2 \mathrm{H}_2 \mathrm{O}(l)+\mathrm{O}_2(g)$

(iii) $\mathrm{AgNO}_3(a q)+\mathrm{KCl}(a q) \longrightarrow \mathrm{AgCl}(s)+\mathrm{KNO}_3(a q)$

(iv) $2 \mathrm{Na}(s)+\frac{1}{2} \mathrm{O}_2(g) \longrightarrow \mathrm{Na}_2 \mathrm{O}(s)$

The number of redox reactions in thsi list is

The volume (in mL ) of 10 volume $\mathrm{H}_2 \mathrm{O}_2$ solution required to completely react with 200 mL of 0.4 M $\mathrm{KMnO}_4$ solution in acidic medium is

$\mathrm{H}_2 \mathrm{O}_2$ with $\mathrm{KMnO}_4$ in acidic medium gives a manganese compound ' $X$ ' and in basic medium gives another manganese compound ' $Y$ '. The oxidation state of manganese in $X$ and $Y$ respectively are