Redox reactions practice · Mixed difficulty

Oxidation number of carbon in graphite

Which of the following is correct representation of a given molecular equation in ionic form?
$6 \mathrm{KI}+2 \mathrm{KMnO}_4+4 \mathrm{H}_2 \mathrm{O} \longrightarrow 3 \mathrm{I}_2+2 \mathrm{MnO}_2+8 \mathrm{KOH}$

In which reaction the underlined substance has been reduced?

In alkaline condition $\mathrm{KMn}{\mathrm{O}_4}$ reacts as follows :$2\mathrm{KMn}{\mathrm{O}_4} + 2\mathrm{KOH} \to 2{\mathrm{K}_2}\mathrm{Mn}{\mathrm{O}_4} + {\mathrm{H}_2}\mathrm{O} + \mathrm{O}\mathrm{.}$ The eq. wt. of $\mathrm{KMn}{\mathrm{O}_4}$ is :

Which can have both +ve and –ve oxidation states?

Which among the following shows maximum oxidation state?

What is the ox. no. of Mn in ${\mathrm{K}_2}\mathrm{Mn}{\mathrm{O}_4}?$

Assertion: Electrons flow in external circuit of galvanic cell while ions flow in internal circuit.
Reason: Direction of current flow is reverse that of electron flow.

Given below are two statements: One is labelled as Assertion A and the other is labelled as Reason R
Assertion A: The reduction of a metal oxide is easier if the metal formed is in liquid state than solid state.
Reason R: The value of $\Delta \mathrm{G}^{\ominus}$ becomes more on negative side as entropy is higher in liquid state than solid state.
In the light of the above statements, choose the most appropriate answer from the options given below

In the titration of $\mathrm{CuS}{\mathrm{O}_4}vs.$ . Hypo in presence of KI, which statement is wrong?

Equivalent mass of $\mathrm{IO}_4^ -$ when it is converted to ${\mathrm{I}_2}$ in acid medium :

A solution of $\mathrm{KMn}{\mathrm{O}_4}$ is reduced to $\mathrm{Mn}{\mathrm{O}_2}.$ The normality of solution is 0.6. The molarity is:

In the reactions;$\mathrm{A}{\mathrm{s}_2}{\mathrm{S}_3} + \mathrm{HN}{\mathrm{O}_3} \to {\mathrm{H}_3}\mathrm{As}{\mathrm{O}_4} + {\mathrm{H}_2}\mathrm{S}{\mathrm{O}_4} + \mathrm{NO}$, the element oxidized is/ are :

In $\mathrm{C} + {\mathrm{H}_2}\mathrm{O} \to \mathrm{CO} + {\mathrm{H}_2};{\mathrm{H}_2}\mathrm{O acts as}:$

The eq. wt. of $\mathrm{F}{\mathrm{e}_3}{\mathrm{O}_4}$ in , $\mathrm{F}{\mathrm{e}_3}{\mathrm{O}_4} + \mathrm{KMn}{\mathrm{O}_4} \to \mathrm{F}{\mathrm{e}_2}{\mathrm{O}_3} + \mathrm{Mn}{\mathrm{O}_2}$ is:

When the ion $\mathrm{C}{\mathrm{r}_2}\mathrm{O}_7^{2 - }$ acts as an oxidant in acidic aqueous solution the ion $\mathrm{C}{\mathrm{r}^{3 + }}\,\mathrm{is}\,\mathrm{formed}.$. How many mole of $\mathrm{S}{\mathrm{n}^{2 + }}$) would be oxidised to $\mathrm{S}{\mathrm{n}^{4 + }}$ by one of $\mathrm{C}{\mathrm{r}_2}\mathrm{O}_7^{2 - }$ ions?

Which of the following reactions are disproportionation reaction?
$\mathrm{(a})\,2\mathrm{C}{\mathrm{u}^ + }\, \to \,\mathrm{C}{\mathrm{u}^{2 + }}\, + \,\mathrm{C}{\mathrm{u}^0}\,$
$\mathrm{(b})\,\mathrm{3MnO}_\mathrm{4}^{\mathrm{2} - }\mathrm{ + 4}{\mathrm{H}^\mathrm{ + }}\, \to \,\mathrm{2MnO}_\mathrm{4}^ - \,\mathrm{ + }\,\mathrm{Mn}{\mathrm{O}_\mathrm{2}}\,\mathrm{ + }\,\mathrm{2}{\mathrm{H}_\mathrm{2}}\mathrm{O}$
$\mathrm{(c)}\,\mathrm{2KMn}{\mathrm{O}_\mathrm{4}}\xrightarrow{\Delta }\,{\mathrm{K}_\mathrm{2}}\mathrm{Mn}{\mathrm{O}_\mathrm{4}}\mathrm{ + Mn}{\mathrm{O}_\mathrm{2}}\,\,\mathrm{ + }\,{\mathrm{O}_\mathrm{2}}$
$\mathrm{(d)}\,\mathrm{2MnO}_\mathrm{4}^ - \, + \,\mathrm{3M}{\mathrm{n}^{2 + }}\, + \,\mathrm{2}{\mathrm{H}_\mathrm{2}}\mathrm{O}\, \to \,5\mathrm{Mn}{\mathrm{O}_2}\mathrm{ + 4}{\mathrm{H}^ \oplus }$
Select the correct option from the following

Respiration is :

Assertion: $\mathrm{Sn}^{2+}$ and $\mathrm{Fe}^{3+}$ can't remain together in a solution.
Reason: $\mathrm{Sn}^{2+}$ and $\mathrm{Fe}^{3+}$ will react mutually to form $\mathrm{Sn}^{4+}$ and $\mathrm{Fe}^{2+}$.

The eq. wt. of $\mathrm{N}{\mathrm{a}_2}{\mathrm{S}_2}{\mathrm{O}_3}$ as reductant, in the reaction, $\mathrm{N}{\mathrm{a}_2}{\mathrm{S}_2}{\mathrm{O}_3} + 5{\mathrm{H}_2}\mathrm{O} + 4\mathrm{C}{\mathrm{l}_2} \to 2\mathrm{NaHS}{\mathrm{O}_4} + 8\mathrm{HCl}:$

In the conversion of $\mathrm{B}{\mathrm{r}_2}$ to $\mathrm{BrO}_3^ -$, the oxidation number of Br changes from

Oxidation state of oxygen in ${\mathrm{H}_2}{\mathrm{O}_2}$ is

In alkaline condition $\mathrm{KMn}{\mathrm{O}_4}$ reacts as follows, $\begin{array}{llllllllllllllllllll} {2\mathrm{KMn}{\mathrm{O}_4} + 2\mathrm{KOH} \to 2{\mathrm{K}_2}\mathrm{Mn}{\mathrm{O}_4} + {\mathrm{H}_2}\mathrm{O} + \mathrm{O}} \end{array}$ Therefore, its equivalent weight will be :

Given :

$\begin{aligned} {XNa}_2 {HAsO}_3+{YNaBrO}_3+{ZHCl} \rightarrow & {NaBr} \\ & +{H}_3 {AsO}_4+{NaCl} \end{aligned}$

The values of ${X}, {Y}$ and ${Z}$ in the above redox reaction are respectively

If equal volumes of 1$M$ $\mathrm{KMn}{\mathrm{O}_4}$ and $1M{\mathrm{K}_2}\mathrm{C}{\mathrm{r}_2}{\mathrm{O}_7}$ solutions are allowed to oxidise ${\mathrm{F}^{2 + }}$ to ${\mathrm{F}^{3 + }}$ in acidic medium volume of oxidant required for one mole of ${\mathrm{F}^{2 + }}$ will be :

Which of the following elements never show positive oxidation number?

Which substance serves as a reducing agent in the following reaction, $14{\mathrm{H}^ + } + \mathrm{C}{\mathrm{r}_2}\mathrm{O}_7^{2 - } + 3\mathrm{Ni} \to 2\mathrm{C}{\mathrm{r}^{3 + }} + 7{\mathrm{H}_2}\mathrm{O} + 3\mathrm{N}{\mathrm{i}^{2 + }}?$

Starch iodide paper is used to test for the presence of:

The oxoacid which acts both as oxidising and reducing agent is :

A substance, that by its sharp colour change indicates the completion of reaction is known as :