Question

Assertion (A) : In Newlands’ octaves, the properties of lithium and sodium were found to be same.​
Reason (R) : Sodium is the eight element after lithium in Newland’s octave.

• A. (A) is true, but (R) is false.
• B. Both (A) and (R) are true, but (R) is not the correct explanation of the (A).
• C. Both (A) and (R) are true, and (R) is correct explanation of the (A).
• D. (A) is false, but (R) is true.

Answer 1

The correct option is C Both (A) and (R) are true, and (R) is correct explanation of the (A).

• According to Newland’s law of octaves, every first element of the group showed similarities in properties with that of the eighth element.​
• Let’s apply this logic here in the given question.
• In Newland’s law of octaves, the properties of lithium and sodium were found to be the same.
• Sodium is the eighth element after lithium in Newland’s octaves. Hence they show similar properties.
• So, both the assertion and reason are true, and the reason is the correct explanation of the assertion.
• Therefore, the correct answer is option A.