$20 \, mL$ of a $1 \, N$ solution of $KMnO_4$ just reacts with $20 \, mL$ of a solution of oxalic acid. The weight of oxalic acid crystals in $1 \, L$ of the solution is $... \, g$

How many $mL$ of $1 \, M$ $H_2SO_4$ is required to neutralize $10 \, mL$ of $1 \, M$ $NaOH$ solution?

Given below are two statements: one is labelled as Assertion $A$ and the other is labelled as Reason $R$.
Assertion $A:$ $3.1500 \ g$ of hydrated oxalic acid dissolved in water to make $250.0 \ mL$ solution will result in $0.1 \ M$ oxalic acid solution.
Reason $R:$ Molar mass of hydrated oxalic acid is $126 \ g \ mol^{-1}$.
In the light of the above statements,choose the correct answer from the options given below:

Reaction of $x \ g$ of $Sn$ with $HCl$ quantitatively produced a salt. The entire amount of the salt reacted with $y \ g$ of nitrobenzene in the presence of the required amount of $HCl$ to produce $1.29 \ g$ of an organic salt (anilinium chloride) quantitatively.
$(1)$ The value of $x$ is. . . . .
$(2)$ The value of $y$ is. . . . .

In the bromination of propyne,$1,1,2,2-$tetrabromopropane is obtained in $27\%$ yield. The amount of $1,1,2,2-$tetrabromopropane obtained from $1 \; g$ of bromine $(Br_2)$ in this reaction is $\dots \; \times 10^{-1} \; g$. (Nearest integer)
(Molar mass: Bromine $(Br)$ $= 80 \; g/mol$)

How many grams of $3-$hydroxypropanal $(MW=74)$ must be dehydrated to produce $7.8 \ g$ of acrolein $(MW=56)$ $(C_3H_4O)$ if the percentage yield is $64\%$? (Round off to the nearest integer).
[Given: Atomic masses: $C = 12.0 \ u, H = 1.0 \ u, O = 16.0 \ u$]