Which of the following aqueous solutions is neutral?

Fill in the blanks given below:
$(i)$ The mass of $1$ mole of a substance expressed in grams is called its .........
$(ii)$ The amount of solute dissolved in $1$ $kg$ of solvent is called its .........
$(iii)$ The Fahrenheit scale in a thermometer is marked between .........
$(iv)$ In $NaCl$,each $Na^{+}$ ion is surrounded by ......... $Cl^{-}$ ions.

When $100 \ mL$ of $1 \ M \ NaOH$ solution and $10 \ mL$ of $10 \ N \ H_2SO_4$ solution are mixed together,the resulting solution will be

Which of the following has the maximum mass?

Mole fraction of $O_2$ in $O_2$ and $O_3$ mixture is $0.25$. Hence percentage concentration $\left( \frac{w}{W} \% \right)$ of $O_2$ in the mixture is:

$200 \ mL$ of a mixture of $50\% \ H_2$,$40\% \ CH_4$ and $10\% \ CO_2$ is exploded with excess of oxygen in an eudiometry tube. The resultant mixture is cooled to room temperature and is passed through $aq. KOH$. Find volume contraction after passing through $KOH$ ................. $mL$