chem mc *2

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1st statement:
Most (not all) acid salts form acidic solutions, but some form slightly alkaline solutions. For example, the solution of NaHCO3 is slightly alkaline (The pH of 0.1 M NaHCO3 solution at 25oC is about 8.31).

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(3):
In chlorine water, the following equilibrium is established:
Cl2(aq) + H2O(l) ≒ H (aq) + Cl-(aq) + HOCl(aq)

When chlorine water is added to sodium chloride solution, the concentration of Cl- ions increases. This increases the backward reaction because Cl- is the reactant of the backward. (in A level, it is said that the equilibrium position shifts to the left.) Therefore, the solution becomes deeper in yellowish-green colour. If the Cl- ions are concentrated enough, chlorine gas may also be formed.

sodium hydrogencarbonate is alkaline, but it is an acid salt.Green gas may be observe, but i am not that sure about it, maybe you can check for further information.

acid salt 當然不是 acid, 可以是neutral或base

chlorine water has a little color, so when it is added , the color of water changes