With reference to 'Silver articles', which of the following statements is/are correct?1.Silver articles turn black after some time when exposed to air.2.It happens due to coating of silver sulphide.Select the correct answer from the code given below:

1. A

   Only 2

   Only 2. The blackening itself is also correct.

2. B

   Neither 1 nor 2

   Neither. Both limbs are the NCERT tarnish pair.

3. C

   Both 1 and 2

   Both 1 and 2. Silver tarnishes black in air; the coat is silver sulphide (Ag2S) from H2S.

4. D

   Only 1

   Only 1. The sulphide coat is also keyed.

Summary. Official key is (c) both. Silver goes black in air because of a silver-sulphide coating. Also note: Ag2S — Silver sulphide tarnish; H2S in air — The sulphur source; Aluminium — Does not tarnish the same way; oxide film; Sterling silver — Alloy; still tarnishes.