In the standardization of $Na_2S_2O_3$ using $K_2Cr_2O_7$ by iodometry,the equivalent weight of $K_2Cr_2O_7$ is

The weight of potassium dichromate (molecular weight $= 294$) required to prepare $250 \ mL$ of $0.04 \ N$ solution is (in $g$)

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

$K_2Cr_2O_7$ is preferred over $Na_2Cr_2O_7$ for use in volumetric analysis as a primary standard because

$2.52 \ g$ of oxalic acid dihydrate was dissolved in $100 \ mL$ of water. $10 \ mL$ of this solution was diluted to $500 \ mL$. The normality of the final solution (in $N$) and the amount of oxalic acid (in $mg/mL$) in the solution are respectively

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: