Acids And Bases

The question assesses our understanding of the trends in acid strength within the group of hydrogen halides: HF, HCl, HBr, and HI.

1. Analyzing Statement I:

The statement given is , indicating that the acid strength increases from HF to HI. This trend is correct. As you move down the group in the periodic table, the size of the halogen atoms increases (F < Cl < Br < I). Hence, the bond strength of the hydrogen-halogen bond decreases. For example, the H-F bond in HF is a strong bond because fluorine is the smallest atom with high electronegativity, resulting in less acidic character as it does not ionize easily. On the other hand, the H-I bond in HI is weaker due to the larger size of iodine, making HI a stronger acid as it readily ionizes. Therefore, Statement I is true.

1. Analyzing Statement II:

The statement explains the reasoning behind the trend in acid strength: as the size of elements increases down the group, the bond strength decreases, leading to an increase in acid strength. This is the correct scientific rationale, as the bond dissociation enthalpy decreases with increasing atomic size, facilitating the release of hydrogen ion (H⁺) and thus, increasing the acid strength. Hence, Statement II is also true.

Considering the above analysis, both statements accurately describe the chemical behavior and provide the correct explanation for the observed trend in acid strength. Therefore, the correct answer is: Both Statement I and Statement II are true.

The task is to match each drug class from List-I with the corresponding drug molecule from List-II. Let's analyze each option:

• Antacids: These are substances that neutralize stomach acidity. The drug molecule Cimetidine is known for its antacid properties, often used to treat gastric acid-related conditions. Thus, (a) matches with (iii).
• Antihistamines: These drugs counteract the effects of histamine in allergic reactions. Seldane is a known antihistamine drug. Hence, (b) matches with (iv).
• Analgesics: These alleviate pain. Morphine is a powerful analgesic. So, (c) matches with (ii).
• Antimicrobials: These inhibit the growth of microorganisms. Salvarsan is an antimicrobial agent historically used to treat diseases like syphilis. Therefore, (d) matches with (i).

Therefore, the correct matching is (B): (a)-(iii), (b)-(iv), (c)- (ii), (d)-(i)