The molarity of a solution of $Na_2CO_3$ having $10.6 \ g$ in $500 \ mL$ of solution is ......... $M$.

$A$ $500 \ g$ toothpaste sample has $0.2 \ g$ fluoride concentration. What is the concentration of $F^-$ in terms of $ppm$ level?

If equal moles of water and urea are taken in a flask,what is the percentage by weight of urea?

The density of $3 \ m$ solution of $NaOH$ is $1.110 \ g \ mL^{-1}$. Calculate the molarity of the solution. (in $M$)

$A$ litre of seawater (which weighs $1030 \ g$) contains $6 \times 10^{-3} \ g$ of dissolved oxygen. The concentration of dissolved oxygen in $ppm$ is:

$10 \ N$ and $\frac{1}{10} \ N$ solutions are called respectively: