Nucleophilic addition reaction will be most favoured in which among the following compounds?

The difference in radii between fourth and third Bohr orbits of \(\mathrm{He}^{+}\)(in m) is

Nitrobenzene on reduction with zinc and \(\mathrm{NH}_4 \mathrm{Cl}\) gives

Identify the set containing isoelectronic species.

The elevation in the boiling point of an aqueous solution of $\mathrm{NaCl}$ is $0.01°\mathrm{C}$. If its van't Hoff factor is $1.92,$ the molality of $\mathrm{NaCl}$ solution is ___$({\mathrm{K}}_{\mathrm{b}}$ for water $=0.52 \mathrm{K} \mathrm{kg} {\mathrm{mol}}^{-1})$

\(A\) and \(B\) are ideal gases. At \(T(K), 2 L\) of ' \(A\) ' with a pressure of 1 bar is mixed with 4 L of ' B ' with a pressure \(\mathrm{p}_{\mathrm{B}}\) bar in a 100 L flask. The pressure exerted by gaseous mixture is 0.1 bar. What is the value of \(p_B\) in bar ?

Identify the reactions in which dichromate acts as an oxidising reagent.
I. \(\mathrm{Cr}_2 \mathrm{O}_7^{2-}+6 \mathrm{Fe}^{2+}+14 \mathrm{H}^{+} \longrightarrow 2 \mathrm{Cr}^{3+}+6 \mathrm{Fe}^{3+}+7 \mathrm{H}_2 \mathrm{O}\)
II. \(\mathrm{Cr}_2 \mathrm{O}_7^{2-}+2 \mathrm{OH}^{-} \longrightarrow 2 \mathrm{CrO}_4^{2-}+\mathrm{H}_2 \mathrm{O}\)
III. \(\mathrm{Cr}_2 \mathrm{O}_7^{2-}+6 \mathrm{I}^{-}+14 \mathrm{H}^{+} \longrightarrow 2 \mathrm{Cr}^{3+}+3 \mathrm{I}_2+7 \mathrm{H}_2 \mathrm{O}\)
IV. \(\mathrm{Na}_2 \mathrm{Cr}_2 \mathrm{O}_7+2 \mathrm{KCl} \longrightarrow \mathrm{K}_2 \mathrm{Cr}_2 \mathrm{O}_7+2 \mathrm{NaCl}\)

The ratio of anion radius to cation radius of a crystal is \(10: 9.3\). Then, the coordination number of the cation in the crystal is

The volume of \(0.1 \mathrm{M} \mathrm{HCl}\) required in \(\mathrm{mL}\) to neutralise \(20 \mathrm{~mL}\) of a solution containing \(0.106 \mathrm{~g}\) of \(\mathrm{Na}_2 \mathrm{CO}_3\) is

\(\left\{x \in R: \cos 2 x+2 \cos ^2 x=2\right\}\) is equal to

A nucleus has mass number \(A_1\) and volume \(V_1\). Another nucleus has mass number \(A_2\) and volume \(V_2\). If the relation the mass numbers is \(\mathrm{A}_2=3 \mathrm{~A}_1\), then \(\frac{\mathrm{V}_1}{\mathrm{~V}_2}=\)

If \(t_r\) is the \(r^{\text {th }}\) term in the expansion of \(\left(2^x+4^{-x}\right)^8\) and if \(t_3=7 t_2\) then \(x=\)

If the roots of the equation \(x^5-40 x^4-P x^3-R x-S=0\) are in geometric progression and the sum of the reciprocals of the roots is 10 , then \(|\mathrm{S}|=\)