lab 7

Question 1

all carbonate salts are soluble in water except?

Answer 1

Na₂CO₃, K₂CO₃, (NH₄)₂CO₃

Question 2

Displacement reaction?

Answer 2

•Stronger acid displaces the weaker acid in its salt

Ex: HCl + Na₂CO₃ ⇒ 2NaCl + H₂CO₃

N.B: The decomposition of carbonates and bicarbonates by dil HCl is a displacement reaction.

Any acid stronger than H₂CO₃ will displace it, thus acetic acid will decompose carbonates.

Question 3

Ka of acids?

Answer 3

• CH₃COOH acetic acid: 1.76*10^-5
• H₂CO₃ carbonyic acid: 4.3*10^-7
• HCN hydrocynic acid: 4.79*10^-9
• H₃BO₃ boric acid: 5.8*10^-10