JEE Chemistry 2025 Question with Solution

Given: Two statements compare Group $13$ and Group $14$ elements.

Find: Which statement is correct and choose the correct option.

For Statement I, first ionisation enthalpy generally increases across a period as effective nuclear charge increases. Therefore, the corresponding Group $14$ element has higher first ionisation enthalpy than the Group $13$ element. So, Statement I is correct.

For Statement II, melting points and boiling points depend on structure and bonding. In general, Group $14$ elements show higher melting and boiling points than the corresponding Group $13$ elements because of stronger network covalent character in many Group $14$ elements. So, Statement II is incorrect.

Therefore, Statement I is correct but Statement II is incorrect. The correct option is A.

Given:

• Statement I: The first ionisation enthalpy of group $14$ elements is higher than the corresponding elements of group $13$.
• Statement II: Melting points and boiling points of group $13$ elements are in general much higher than those of the corresponding elements of group $14$.

Find: The most appropriate answer.

1. Statement I

• Ionisation enthalpy is the energy required to remove the outermost electron from a gaseous atom.
• Across a period, ionisation enthalpy generally increases because nuclear charge increases.
• Hence, corresponding Group $14$ elements have higher first ionisation enthalpy than Group $13$ elements.
• Therefore, Statement I is correct.

2. Statement II

• Melting point and boiling point depend on bonding and structure.
• In general, corresponding Group $14$ elements have higher melting and boiling points than Group $13$ elements.
• Therefore, the statement that Group $13$ elements have much higher melting and boiling points is false.
• Hence, Statement II is incorrect.

Therefore, the correct conclusion is: Statement I is correct but Statement II is incorrect. So, the correct option is A.