A hydrocarbon ' $\mathrm{X}$ ' with formula $\mathrm{C}_{6} \mathrm{H}_{8}$ uses two moles of $\mathrm{H}_{2}$ on catalytic hydrogenation of its one mole. On ozonolysis, ' $\mathrm{X}$ ' yields two moles of methane dicarbaldehyde. The hydrocarbon ' $\mathrm{X}$ ' is:

Given below are two statements :

Statement I: Upon heating a borax bead dipped in cupric sulphate in a luminous flame, the colour of the bead becomes green

Statement II: The green colour observed is due to the formation of copper(I) metaborate

In light of the above statements, choose the most appropriate answer from the options given below :

In the following halogenated organic compounds, the one with the maximum number of chlorine atoms in its structure is :

The incorrect statement for the use of indicators in acid-base titration is :