Determine the oxidation number (oxidation state) of each element in CH 4 . C : H : Determine the oxidation number (oxidation state) of each element in SO 2 . S : O : Determine the oxidation number (oxidation state) of each element in BF 3 . B : F :

1. In CH₄ molecule:

The oxidation number of H = (+ 1)

The oxidation number of C = (- 4)

2. In SO₂ molecule:

The oxidation number of O = (- 2)

the oxidation number of S = (+ 4)

3. In BF₃ molecule:

The oxidation number of F = (- 1)

the oxidation number of B = (+ 3)

Explanation:

Oxidation number represents the oxidation state of an element in a given chemical compound, which can be zero, negative or positive.

The overall charge on a given chemical molecule is equal to sum of the oxidation numbers of all the elements in that molecule.

Now, calculating the oxidation number-

1. In CH₄ molecule:

As we know, the oxidation number of H = (+ 1)

and the overall charge on the molecule = 0

Let the oxidation number of C be x

∴ x + (+ 1) × 4 = 0

⇒ x = (- 4)

Therefore, the oxidation number of C = (- 4)

2. In SO₂ molecule:

As we know, the oxidation number of O = (- 2)

and the overall charge on the molecule = 0

Let the oxidation number of S be x

∴ x + (- 2) × 2 = 0

⇒ x = (+ 4)

Therefore, the oxidation number of S = (+ 4)

3. In BF₃ molecule:

As we know, the oxidation number of F = (- 1)

and the overall charge on the molecule = 0

Let the oxidation number of B be x

∴ x + (- 1) × 3 = 0

⇒ x = (+ 3)

Therefore, the oxidation number of B = (+ 3)

i'm assuming that the correct answer is indeed the first one/ "a"..

the answer is b because, investigating whether another species of moth also drinks tears might be interesting, but it would not directly explain why this species of moth does.

to explain why this species of moth drinks tears, the scientist could ask: "what nutrients that moths need are in elephant tears? "

the scientist could experiment with moth repellent or oter ways to keep the moths away, but that would not answer his original question.