The mass of a mixture containing $NaCl$ and $NaBr$ is $4.0 \ g$. If $Na$ is $30 \%$ of the total mixture,the composition of $NaCl$ in the mixture is (in $\%$)

In an experiment,it was shown that $10 \ mL$ of a $0.05 \ M$ solution of a chloride required $10 \ mL$ of a $0.1 \ M$ solution of $AgNO_3$. Which of the following will be the formula of the chloride ($X$ stands for the symbol of the element other than chlorine)?

$x$ grams of calcium carbonate was completely burnt in air. The weight of the solid residue formed is $28 \,g$. What is the value of $x$ (in grams)?

$A$ 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 $M$?

If $100 \ mL$ of $1 \ N$ sulphuric acid were mixed with $100 \ mL$ of $1 \ M$ sodium hydroxide,the solution will be

$1\, g$ of a carbonate $(M_{2}CO_{3})$ on treatment with excess $HCl$ produces $0.01186\, mol$ of $CO_{2}.$ The molar mass of $M_{2}CO_{3}$ in $g\, mol^{-1}$ is: