Given below are two statements :

Statement I : The second ionisation enthalpy of Na is larger than the corresponding ionisation enthalpy of Mg .

Statement II : The ionic radius of $\mathrm{O}^{2-}$ is larger than that of $\mathrm{F}^{-}$.

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

Both human DNA and RNA are chiral molecules. The chirality in DNA and RNA arises due to the presence of

A student has been given a compound " $x$ " of molecular formula- $\mathrm{C}_6 \mathrm{H}_7 \mathrm{~N}$. ' $x$ ' is sparingly soluble in water. However, on addition of dilute mineral acid, ' $x$ ' becomes soluble in water. ' $x$ ' when treated with $\mathrm{CHCl}_3$ and $\mathrm{KOH}(\mathrm{alc})$, ' $y$ ' is produced. ' $y$ ' has a specific unpleasant smell. On treatment with benzenesulphonyl chloride, ' $x$ ' gives a compound ' $z$ ' which is soluble in alkali. The number of different " H " atoms present in ' z ' is:-

Identify the INCORRECT statements from the following :

A. Notation ${ }_{12}^{24} \mathrm{Mg}$ represents 24 protons and 12 neutrons.

B. Wavelength of a radiation of frequency $4.5 \times 10^{15} \mathrm{~s}^{-1}$ is $6.7 \times 10^{-8} \mathrm{~m}$.

C. One radiation has wavelength $=\lambda_1(900 \mathrm{~nm})$ and energy $=\mathrm{E}_1$. Other radiation has wavelength $=\lambda_2(300 \mathrm{~nm})$ and energy $=\mathrm{E}_2 \cdot \mathrm{E}_1: \mathrm{E}_2=3: 1$.

D. Number of photons of light of wavelength 2000 pm that provides 1 J of energy is $1.006 \times 10^{16}$.

Choose the correct answer from the options given below :