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

Iodine and hypo react to produce

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:

The required amount of crystalline oxalic acid (equivalent weight = $63$) to prepare $250 \, mL$ of $N/10$ oxalic acid solution is: (in $, g$)

Identify the incorrect statements regarding primary standard of titrimetric analysis.
$(A)$ It should be purely available in dry form.
$(B)$ It should not undergo chemical change in air.
$(C)$ It should be hygroscopic and should react with another chemical instantaneously and stoichiometrically.
$(D)$ It should be readily soluble in water.
$(E)$ $KMnO_4$ and $NaOH$ can be used as primary standard.
Choose the correct answer from the options given below:

When nitrogen gas is passed through $100 \ mL$ of $0.1 \ M$ $H_2SO_4$ containing $0.30 \ g$ of an organic compound,the ammonia evolved is neutralized. To neutralize the excess acid,$20 \ mL$ of $0.5 \ M$ $NaOH$ is required. Identify the organic compound.