Molarity of a solution prepared by dissolving $75.5 \ g$ of pure $KOH$ in $540 \ mL$ solution is .......... $M$

$A$ $1000 \ g$ aqueous solution of $CaCO_3$ contains $10 \ g$ of calcium carbonate. The concentration of the solution in $ppm$ is .........

$A$ solution containing $200 \ mL$ of $0.5 \ M$ $KCl$ is mixed with $50 \ mL$ of $19 \% \ w/v$ $MgCl_2$ and the resulting solution is diluted $8$ times. What is the molarity of the chloride ion in the final solution?

The volume of $10 \ N$ and $4 \ N$ $HCl$ required to make $1 \ L$ of $7 \ N$ $HCl$ are

Sea water,which can be considered as a $6 \ M$ solution of $NaCl$,has a density of $2 \ g \ mL^{-1}$. The concentration of dissolved oxygen $(O_2)$ in sea water is $5.8 \ ppm$. Then the concentration of dissolved oxygen $(O_2)$ in sea water is $x \times 10^{-4} \ m$. $x = ............$ $(Nearest \ integer)$
Given: Molar mass of $NaCl$ is $58.5 \ g \ mol^{-1}$. Molar mass of $O_2$ is $32 \ g \ mol^{-1}$.

The molarity of pure water at $4\,^{\circ}C$ is ............... $M$.