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

In the iodometric estimation in the laboratory,which process is involved?

$500 \ mL$ 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)

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

Given below are two statements: One is labelled as Assertion $A$ and the other is labelled as Reason $R$.
Assertion $A$: Permanganate titrations are not performed in the presence of hydrochloric acid.
Reason $R$: Chlorine is formed as a consequence of the oxidation of hydrochloric acid.
In the light of the above statements,choose the correct answer from the options given below.

Identify the correct statements:
$A$. Hydrated salts can be used as primary standard.
$B$. Primary standard should not undergo any reaction with air.
$C$. Reactions of primary standard with another substance should be instantaneous and stoichiometric.
$D$. Primary standard should not be soluble in water.
$E$. Primary standard should have low relative molar mass.
Choose the correct answer from the options given below :