Abuffer of ph 4.1 is to be prepared from a weak acid and its salt. the best acid from which to prepare the buffer is a. phthalic acid, k1 = 1.3 × 10-3 (first ionization) b. hydrogen phthalate, k2 = 3.9 × 10-5 (second ionization of phthalic acid) c. benzoic acid, k = 6.3 × 10-5 d. hydrocyanic acid, k = 4.0 × 10-10

1.

Solid: A, B, and C.

Liquid: D and E.

Gas: F.

2.

Into liquid on warm day (37 °C): D and C.

Into a liquid only when heated slightly: C and E.

From liquid to solid readily when placed into a freezer (0 °C): D.

Explanation:

Hello!

In this case, since the melting point is the temperature at which a substance change from solid to liquid and the boiling point from liquid to gas, we understand that substance at a temperature below the melting point is solid, whereas above are liquid; moreover, below the boiling point they are liquid and above gaseous.

In such a way, we have:

1.

Solid: A, B, and C.

Liquid: D and E.

Gas: F.

2.

Into liquid on warm day (37 °C): D and C.

Into a liquid only when heated slightly: C and E.

From liquid to solid readily when placed into a freezer (0 °C): D.

Best regards!