The mass of sodium acetate $(CH_3COONa)$ required to prepare $250 \ mL$ of $0.35 \ M$ aqueous solution is . . . . . . $g$. (Molar mass of $CH_3COONa$ is $82.02 \ g \ mol^{-1}$)

$X \ g$ of $Ca$ [atomic mass $= 40$] dissolves completely in concentrated $HCl$ solution to produce $5.04 \ L$ of $H_2$ gas at $STP$. The value of $X$ is closest to

Assuming complete decomposition,the volume of $CO_2$ released at $STP$ on heating $9.85 \ g$ of $BaCO_3$ (Atomic mass of $Ba = 137$) will be ................ $L$.

What volume of $H_2$ gas in liters at $1 \, \text{atm}$ pressure and $273 \, K$ temperature is required to reduce $21.6 \, g$ of boron trichloride $(BCl_3)$ (atomic weight of $B = 10.8$) to obtain boron?

Ferrous sulphate heptahydrate is used to fortify foods with iron. The amount (in $grams$) of the salt required to achieve $10 \; ppm$ of iron in $100 \; kg$ of wheat is
Atomic weight : $Fe = 55.85$,$S = 32.0$,$O = 16.00$

What volume of $O_{2(g)}$ measured at standard condition will be formed by the action of $100 \ mL$ of $0.5 \ N \ KMnO_4$ on hydrogen peroxide in an acidic solution? The skeleton equation for the reaction is:
$KMnO_4 + H_2SO_4 + H_2O_2 \to KHSO_4 + MnSO_4 + O_2 + H_2O$
(Answer in $L$)