Question

1.

A 1.00 liter solution contains 0.41 M nitrous acid and 0.53 M sodium nitrite.

If 0.130 moles of calcium hydroxide are added to this system, indicate whether the following statements are true or false.

(Assume that the volume does not change upon the addition of calcium hydroxide.)

_______TrueFalseA. The number of moles of HNO₂ will remain the same.

_______TrueFalseB. The number of moles of NO₂^- will remain the same.

_______TrueFalseC. The equilibrium concentration of H₃O⁺ will remain the same.

_______TrueFalseD. The pH will increase.

_______TrueFalseE. The ratio of [HNO₂] / [NO₂^-] will decrease.

Answer 1

HNO2 is acid

NO2- is its conjugate base

When more OH- is added in form of Ca(OH)2

HNO2 will react with added OH- to form more NO2-

So,

The number of HNO2 would decrease

A is false

The number of NO2- will increase

B is false

Since base is added, OH- would increase and H+ would decrease

C is false

Since H+ is decreasing, pH will increase

D is false

Since HNO2 is decreasing and NO2- is increasing.

The ratio [HNO2]/[NO2-] would decrease

E is true

false

false

false

false

true