$KMnO_4$ reacts with oxalic acid according to the equation:
$2MnO_4^- + 5C_2O_4^{2-} + 16H^+ \to 2Mn^{2+} + 10CO_2 + 8H_2O$
Here,$20 \ mL$ of $0.1 \ M$ $KMnO_4$ is equivalent to:

Change in volume when $10 \, mL$ of phosphine $(PH_3)$ is decomposed according to the reaction: $2PH_{3(g)} \rightarrow 2P_{(s)} + 3H_{2(g)}$.

What volume of $CO_2$ at $STP$ is obtained by thermal decomposition of $20 \ g$ $KHCO_3$? [Atomic weight of $K = 39$]
$2KHCO_{3(s)} \to K_2CO_{3(s)} + CO_{2(g)} + H_2O_{(g)}$

If $2 \ g$ of $NaOH$ is dissolved in water to make a $100 \ cm^3$ solution,what is the normality of this solution?

At sea level,the dry air mass percentage composition is given as nitrogen gas: $70.0$,oxygen gas: $27.0$,and argon gas: $3.0$. If the total pressure is $1.15 \ atm$,calculate the ratio of the following respectively:
$(i)$ partial pressure of nitrogen gas to partial pressure of oxygen gas
$(ii)$ partial pressure of oxygen gas to partial pressure of argon gas
(Given: Molar mass of $N_2$,$O_2$,and $Ar$ are $28, 32$,and $40 \ g \ mol^{-1}$ respectively)

Given the reaction $C_{(s)} + H_2O_{(l)} \to CO_{(g)} + H_{2(g)}$,calculate the volume of the gases produced at $STP$ from $48.0 \ g$ of carbon.