The production of nascent hydrogen occurs when a metal reacts with an acid or an alkali and forms hydrogen gas. In an alkaline medium, nascent hydrogen is produced by the reaction of certain metals with hydroxide ions.
Among the given metal pairs:
1. Zn and Al: Both zinc (Zn) and aluminum (Al) can react with alkaline solutions to produce nascent hydrogen. Zinc reacts with alkalis to form hydrogen gas, and aluminum can react with alkali (especially when heated or in excess) to produce nascent hydrogen as well.
2. Fe and Ni: Both iron (Fe) and nickel (Ni) are less reactive in producing nascent hydrogen in alkaline media compared to the metals in other pairs.
3. Al and Mg: Magnesium (Mg) also reacts with alkalis to produce nascent hydrogen, but aluminum (Al) is more commonly known to produce nascent hydrogen when reacting with alkalis.
4. Mg and Zn: Magnesium reacts with alkaline solutions to form nascent hydrogen, but zinc is also quite reactive in alkaline solutions, although Al and Zn are more significant producers.
Answer: Zn and Al
Given below are two statements:
Statement (I): The first ionization energy of Pb is greater than that of Sn.
Statement (II): The first ionization energy of Ge is greater than that of Si.
In light of the above statements, choose the correct answer from the options given below:
The product (A) formed in the following reaction sequence is:

\[ \begin{array}{|c|c|} \hline \textbf{LIST-I (Redox Reaction)} & \textbf{LIST-II (Type of Redox Reaction)} \\ \hline A. \, CH_4(g) + 2O_2(g) \rightarrow CO_2(g) + 2H_2O(l) & I. \, \text{Disproportionation reaction} \\ B. \, 2NaH(s) \rightarrow 2Na(s) + H_2(g) & II. \, \text{Combination reaction} \\ C. \, V_2O_5(s) + 5Ca(s) \rightarrow 2V(s) + 5CaO(s) & III. \, \text{Decomposition reaction} \\ D. \, 2H_2O(aq) \rightarrow 2H_2(g) + O_2(g) & IV. \, \text{Displacement reaction} \\ \hline \end{array} \]

A quantity \( X \) is given by: \[ X = \frac{\epsilon_0 L \Delta V}{\Delta t} \] where:
- \( \epsilon_0 \) is the permittivity of free space,
- \( L \) is the length,
- \( \Delta V \) is the potential difference,
- \( \Delta t \) is the time interval.
The dimension of \( X \) is the same as that of: