Q. Dalton’s atomic theory successfully explained

The correct answer is Option C: i, ii, and iv.

Explanation:

Dalton’s atomic theory

Dalton’s atomic theory was a significant milestone in the development of modern chemistry. It successfully explained the following laws:

1. Law of Conservation of Mass: This law states that mass is neither created nor destroyed in a chemical reaction. Dalton’s theory explained this by proposing that atoms are indivisible and cannot be created or destroyed during chemical reactions. Instead, they are rearranged to form new substances.

2. Law of Constant Composition: This law states that a given compound always contains the same elements in the same proportion by mass. Dalton’s theory supported this by suggesting that compounds are formed by the combination of atoms of different elements in fixed ratios.

3. Law of Multiple Proportions: This law states that when two elements combine to form more than one compound, the masses of one element that combine with a fixed mass of the other are in the ratio of small whole numbers. Dalton’s theory explained this by stating that atoms combine in simple whole-number ratios to form compounds.

However, Dalton’s atomic theory did not address or explain the Law of Radioactivity, as radioactivity was discovered much later (by Henri Becquerel in 1896) and involves the breakdown of atomic nuclei, which was beyond the scope of Dalton’s original theory.

Thus, the correct answer is Option C: i, ii, and iv.