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

Why is it essential to wash the precipitate with water before estimating it quantitatively?

$500 \ mL$ 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)

When potassium permanganate is titrated against ferrous ammonium sulphate,the equivalent weight of potassium permanganate is

Given below are two statements
Statement $I$: Aqueous solution of $K_2Cr_2O_7$ is preferred as a primary standard in volumetric analysis over $Na_2Cr_2O_7$ aqueous solution.
Statement $II$: $K_2Cr_2O_7$ has a higher solubility in water than $Na_2Cr_2O_7$.
In the light of the above statements,choose the correct answer from the options given below:

The ammonia evolved from the treatment of $0.30 \, g$ of an organic compound for the estimation of nitrogen was passed in $100 \, mL$ of $0.1 \, M$ sulphuric acid. The excess of acid required $20 \, mL$ of $0.5 \, M$ sodium hydroxide solution for complete neutralization. The organic compound is: