Which of the following methods is useful for producing semiconductor grade metals of high purity ?

If \(r_1, r_2\) and \(r_3\) represent the most probable speeds of three different gases at the same temperature as shown in figure with molar masses \(M_1, M_2\) and \(M_3\) respectively. The correct order of molar masses of these gases is

Match List-I with List-II
\(\begin{array}{|c|l|l|l|}\hline & \text{List-I (Reaction)} & & \text{List-II (Enzyme)} \\ \hline \text{A.} & \begin{array}{l} \text{Hydrolysis of starch to} \\ \text{maltose}\end{array} & \text{I} & \text{Diastase} \\ \hline \text{B.} & \begin{array}{l} \text{Conversion of proteins} \\ \text{to peptides} \end{array} & \text{II} & \text{Pepsin} \\ \hline \text{C.} & \begin{array}{l} \text{Hydrolysis of sucrose} \\ \text{to glucose and fructose}\end{array} & \text{III} & \text{Invertase} \\ \hline \text{D.} & \text{Glucose to ethanol} & \text{IV} & \text{Zymase} \\ \hline\end{array}\)
The correct answer is

When a current of \(0.5 \mathrm{~A}\) is passed for 2 hours through a molten metal salt, \(3.88 \mathrm{~g}\) of the metal was deposited. If atomic mass of the metals is 208 units, the oxidation state of the metal in the salt is

Assertion (A) White tin is an example of tetragonal system.Reasoning (R) For a tetragonal system \(a=b=c\) and \(\alpha=\beta=\gamma \neq 90^{\circ}\). The correct answer is

For which one of the following elements, ${\mathrm{M}}^{3+}\mid {\mathrm{M}}^{2+}$ standard electrode potential is more positive?

In lanthanide series, the element well known to exhibit +4 oxidation state is

For a binomial distribution with mean 6 and variance \(\mathrm{P}(\mathrm{X} \geq 2)=\)

The angle between the electric dipole moment of a dipole and the electric field strength due to it on the equatorial line is

If the radius of electron in the excited state of \(\mathrm{He}^{+}\)is \(0.4232 \mathrm{~nm}\), the energy of electron in that excited state in \(\mathrm{J}\) is :
(The radius and energy of electron in the first orbit of hydrogen atom are \(52.9 \mathrm{pm}\) and \(-2.18 \times 10^{-18} \mathrm{~J}\) respectively)

Consider the following cell reaction
\(2 \mathrm{Fe}^{3+}(\mathrm{aq})+2 \mathrm{I}^{-}(\mathrm{aq}) \rightleftharpoons 2 \mathrm{Fe}^{2+}(\mathrm{aq})+\mathrm{I}_2(\mathrm{~s})\)
At 298 K, the cell emf is 0.237 V. The equilibrium constant for the reaction is \(10^x\). The value of \(x\) is
\(\left(\mathrm{F}=96500 \mathrm{C} \mathrm{~mol}^{-1} ; \mathrm{R}=8.3 \mathrm{~J} \mathrm{~K}^{-1} \mathrm{~mol}^{-1}\right)\)

If \(f(x)=\left\{\begin{array}{ll}3 a x-2 b, & x\gt1 \\ a x+b+1, & x \lt 1\end{array}\right.\) and \(\lim _{x \rightarrow 1} f(x)\) exists, then the relation between \(a\) and \(b\) is

The correct order of acidic character of group- 16 hydrides is