Arrange the following 0.10 M aqueous solutions in order of increasing pH: a. NaOH
b. HBr
c. NaCH3CO2
d. KBr
e. NH4Br.

The correct answer is HBr<NH4Br<KBr<NaCH3CO2<NaOH.

Explanation:

When salt is added to the water, the formation of acid and base takes place. The pH helps in predicting the basicity, acidity, and neutrality of a compound.

It is known that NaOH is a strong base, thus, its solution will be basic, and therefore, the pH of NaOH will be greater than 7.

The solution of HBr will be acidic as HBr is the strong acid, thus, its pH will be less than 7.

In dissolving NaCH3CO2 in water, the formation of CH3COOH, which is a weak acid, and NaOH that is, a strong base takes place. Therefore, as NaOH is the strong base, the solution will be basic, and the pH of NaCH3CO2 will be greater than 7.

On dissolving KBr in water, HBr, that is, a strong acid, and KOH, that is, a strong base is produced. Therefore, as HBr is the strong acid, and KOH is the strong base, the solution will be neutral. Thus, the pH of KBr will be equivalent to 7.

On dissolving NH4Br in water, the formation of HBr, that is, strong acid, and NH4OH, that is, the weak base takes place. Therefore, as HBr is the strong acid, the solution will be acidic, and the pH of NH4Br will be less than 7.

Hence, the increasing order of pH of 0.10 M aqueous solution will be,

HBr<NH4Br<KBr<NaCH3CO2<NaOH

okay yes , aha.

c. heat could easily travel through the molecules in the air and escape/enter the flask. removing the air slows down the heat transfer.