List of top Chemistry Questions on Redox Reactions

$\text{PQ}_2$ is a sparingly soluble salt with solubility product $\text{K}_{sp} = 4 \times 10^{-12}$ in aqueous medium at some given temperature. It is observed that upon addition of a highly soluble salt RQ at the same temperature, the solubility of $\text{PQ}_2$ drops by a factor of 100. The concentration (in millimoles per litre) of added RQ in the solution is closest to:

Consider the following chemical reactions performed at identical temperature and volume:
Experiment I: $\text{X(g)} \rightleftharpoons 2\text{Y(g)}$
Experiment II: $\text{X(g)} \rightleftharpoons \text{Z(g)}$
The partial pressure of the reactant and product are denoted, respectively, by $p_{\text{reactant}}$ and $p_{\text{product}}$ during the course of the reactions. Assuming ideal gas behaviour, the correct plot of $p_{\text{reactant}}$ versus $p_{\text{product}}$ for Experiments I and II is:

Consider two reactions.
I. A zero order reaction: $\text{X} \rightarrow P_1$.
II. A first order reaction: $\text{Y} \rightarrow P_2$.
Both reactions begin simultaneously with the same initial concentration `C', that is $\text{X}_0 = \text{Y}_0 = \text{C}$. It is observed that the concentrations of the reactants fall to one-third of their initial values at the same time, provided the rate constants satisfy a certain ratio. If $k_0$ and $k_1$ denote, respectively, the zero and first order rate constants then the ratio $k_0/k_1$ necessary for this condition to be satisfied is:

Consider the following species:
(i) $\text{ClO}^-$
(ii) $\text{ClO}_2^-$
(iii) $\text{ClO}_3^-$
(iv) $\text{ClO}_4^-$
Among them, the species that undergoes(undergo) disproportionation reactions is(are):

Two galvanic cells, Cell I and Cell II, operate at the same temperature and involve two different redox systems. It is observed that at a particular value of the reaction quotient $\text{Q}_{\text{I}} = \text{Q}_{\text{II}} = \text{Q}_0$, the ratio of EMF of the two cells ($\text{E}_{\text{I}}/\text{E}_{\text{II}}$) as well as the ratio of change of Gibbs free energy for the two cells ($\Delta\text{G}_{\text{I}}/\Delta\text{G}_{\text{II}}$) are both 1/3. Assuming standard cell reactions written in the spontaneous direction and reversible operation, the pair of cells can satisfy these conditions is:

The following reaction can be best described as: \[ 3\mathrm{MnO_4^{2-}}+4\mathrm{H^+} \rightarrow 2\mathrm{MnO_4^-} +\mathrm{MnO_2} +2\mathrm{H_2O} \]

Consider the following reaction: \[ xMnO_4^- + yI^- + zH^+ \rightarrow pMn^{2+} + qIO_3^- + rH_2O \] The correct ratio \(x:y\) in the balanced equation is:

The violet colour of \(KMnO_4\) solution is due to:

\( \mathrm{MnO_4^{2-}} \) in acidic medium disproportionates to :

Acidified KMnO$_4$ oxidizes sulphite to:

State Faraday’s first law of electrolysis. How much electricity, in terms of Faraday, is required to reduce one mole of MnO4− to Mn2+ ion?

Complete and balance the following chemical equations:
(a) \(\text{MnO}_4^- + \text{C}_2\text{O}_4^{2-} + \text{H}^+ \to \) (b) \(\text{KMnO}_4 \xrightarrow{\text{Heat}} \) (c) \(\text{Cr}_2\text{O}_7^{2-} + \text{H}_2\text{S} + \text{H}^+ \to \)

Formaldehyde undergoes Cannizzaro reaction because
(A) It has alpha-hydrogen atom.
(B) It does not have alpha-hydrogen atom.
(C) It does not undergo self-oxidation and reduction on heating with concentrated alkali.
(D) It undergoes self-oxidation and reduction on heating with concentrated alkali.

Out of KMnO4 and K2MnO4, which one is paramagnetic and why?

\(MnO_4^-\) + H₂O + I^- → MnO₂ + OH^- + X
Compound ‘X’ in the above reaction is :