$500 \ mL$ of $1.2 \ M$ $KI$ solution is mixed with $500 \ mL$ of $0.2 \ M$ $KMnO_4$ solution in basic medium. The liberated iodine was titrated with standard $0.1 \ M$ $Na_2S_2O_3$ solution in the presence of starch indicator till the blue color disappeared. The volume (in $L$) of $Na_2S_2O_3$ consumed is . . . . . . . (Nearest integer)

With $63 \ g$ of oxalic acid,how many litres of $\frac{N}{10}$ solution can be prepared?

The primary standard solution for the estimation of $Na_2S_2O_3$ is:

$FeSO_4 \cdot (NH_4)_2SO_4 \cdot 6H_2O$ is called:

The weight of oxalic acid that will be required to prepare a $1000 \ mL$ $(N / 20)$ solution is

Below are two statements. One is labeled as Assertion $(A)$ and the other as Reason $(R).$
Assertion $(A):$ When using an aqueous solution of $KOH$ in a volumetric analysis,its concentration should be checked before use.
Reason $(R):$ $KOH$ solution absorbs atmospheric $CO_2$ when it gets old.
In the context of the above statements,choose the correct answer from the options given below: