$A$ metal chloride contains $71\%$ chlorine by mass and has a vapor density of $50$. What is the atomic mass of the metal?

$60 \ mL$ $NaOH$ solution is required for complete neutralization of $0.98 \ g$ orthophosphoric acid. The concentration of $NaOH$ solution is ............. $M$.

At $298 \ K$,equal volumes of $SO_2, CH_4$ and $O_2$ are mixed in an empty container. The total pressure exerted is $2.1 \ atm$. The partial pressure of $CH_4$ in the mixture is $.......... \ atm$.

The heat of combustion of methane is $-800 \ kJ \ mol^{-1}$. What is the heat of combustion for $4 \times 10^{-4} \ kg$ of methane?

White phosphorus reacts with chlorine and the product hydrolyses in the presence of water. Calculate the mass of $HCl$ obtained by the hydrolysis of the product formed by the reaction of $62 \ g$ of white phosphorus with chlorine in the presence of water.

$20 \ mL$ of sodium iodide solution gave $4.74 \ g$ silver iodide when treated with excess of silver nitrate solution. The molarity of the sodium iodide solution is $........ M$. $(Nearest \ Integer \ value)$
$(Given: Na=23, I=127, Ag=108, N=14, O=16 \ g \ mol^{-1})$