Three solutions of $HCl$ having normalities $12 \ N$,$6 \ N$,and $2 \ N$ are mixed to obtain a solution of $4 \ N$ normality. Which among the following volume ratios is incorrect for the above mixture?

One mole of methanol when burnt in excess of $O_2$ releases $723 \ kJ \ mol^{-1}$ of heat. If $1 \ mol$ of $O_2$ is used,what will be the amount of heat evolved in $kJ$?

In an experiment on the enthalpy of neutralisation of sodium hydroxide with sulphuric acid,$50 \ cm^3$ of $0.4 \ M$ sodium hydroxide were titrated thermometrically with $0.25 \ M$ sulphuric acid. Which of the following plots gives the most probable correct representation of the temperature of the solution (initial temperatures of $NaOH$ and $H_2SO_4$ are the same)?

The composition of a sample of wustite is $Fe_{0.93} O_{1.00}$. The percentage of iron in the form of $Fe^{3+}$ ion is nearly:

$10 \ mL$ of conc. $H_2SO_4$ $(18 \ M)$ is diluted to $1 \ L$. The approximate strength of the dilute acid is $........... \ N$.

How many moles of $H_2O_2$ are required to decolorize $1$ mole of $KMnO_4$ (in $.5$)?