Which of the following is the most stable alkene?

Which of the following substances combines with hemoglobin in the blood to form carboxyhemoglobin?

$X$ and $Y$ are two metals. When burnt in air,$X$ forms only oxide while $Y$ forms oxide and nitride. The metals $X$ and $Y$ may be

The masses of neutron,proton and deuteron in amu are $1.00893$,$1.00813$ and $2.01473$,respectively. The packing fraction of the deuteron in amu is

The major products obtained from the reactions in List$-II$ are the reactants for the named reactions mentioned in List$-I.$ Match each entry in List$-I$ with the appropriate entry in List$-II$ and choose the correct options.

List$-I$	List$-II$
$(P)$ Stephen reaction	$(1)$ Toluene $\xrightarrow{\substack{\text { (i) } CrO _2 Cl _2 / CS _2 \\ \text { (ii) } H _3 O +}}$
$(Q)$ Sandmeyer reaction	$(2)$ Benzoic acid $\xrightarrow{\substack{\text { (i) } PCl _5 \\ \text { (iii) } NH _3 \\ \text { (iii) } P _4 O _{10}, \Delta}}$
$(R)$ Hoffmann bromamide degradation reaction	$(3)$ Nitrobenzene $\xrightarrow{\begin{array}{l}\text { (i) } Fe , HCl \\ \text { (ii) } HCl , NaNO _2 \\ \text { (273-278 K), } H _2 O \end{array}}$
$(S)$ Cannizzaro reaction	$(4)$ Toluene $\xrightarrow{\begin{array}{l}\text { (i) } Cl _2 / hv , H _2 O \\ \text { (ii) } \text {Tollen 's reagent } \\ \text { (iii) } SO _2 Cl _2 \\ \text { (iv) } NH _3\end{array}}$
	$(5)$ Aniline $\xrightarrow{\substack{\text { (i) }\left( CH _3 CO \right)_2 O , \text { Pyridine } \\ \text { (ii) } HN O _3 H _{2} SO _4, 288 K \\ \text { (iii) } aq . NaOH }}$

In the circuit shown here,$E_1 = E_2 = E_3 = 2 \, V$ and $R_1 = R_2 = 4 \, \Omega$. The current flowing between points $A$ and $B$ through battery $E_2$ is