$A$ solution of $20.2 \, g$ of $1,2$-dibromopropane in $MeOH$ upon heating with excess $Zn$ produces $3.58 \, g$ of an unsaturated compound $X$. The yield $(\%)$ of $X$ is closest to [Atomic weight of $Br$ is $80$].

$A$ $6 \ L$ sample of hard water has a total hardness of $200 \ ppm$ of $Mg^{2+}$ in the form of bicarbonates and chlorides. This sample is treated with $Na_2CO_3$ to eliminate all temporary hardness,and the new hardness is found to be $\frac{1000}{3} \ ppm$ of $CaCO_3$. Find the mass of $MgCl_2$ in the $6 \ L$ sample in $mg$. $(d_{H_2O} = 1 \ g/mL)$

What quantity of ammonium sulphate is necessary for the production of $NH_3$ gas sufficient to neutralize a solution containing $292 \ g$ of $HCl$? $(HCl=36.5, (NH_4)_2SO_4=132, NH_3=17)$

$A$ sample of $NaOH$ weighing $0.38 \ g$ is dissolved in water to make $50.0 \ mL$ of solution in a volumetric flask. What is the molarity of the resulting solution in $M$?

How many litres of $CO_2$ at $STP$ will be formed when $100 \ mL$ of $0.1 \ M \ H_2SO_4$ reacts with excess of $Na_2CO_3$?

$A$ sample of $CaCO_3$ and $MgCO_3$ weighing $2.21 \ g$ is ignited to a constant weight of $1.152 \ g$. The composition of the mixture is:
(Given molar mass in $g \ mol^{-1}: CaCO_3 = 100, MgCO_3 = 84$)