A 1.00 liter solution contains 0.31 M hydrocyanic acid and 0.40 M sodium cyanide. If 0.100 moles of barium 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 barium hydroxide.) a. The number of moles of HCN will remain the same.
b. The number of moles of CN will decrease.
c. The equilibrium concentration Of H3O+ will increase.
d. The pH will increase.
e. The ratio of [HCN]/ [CN-] will remain the same.

Explanation:

acid --> HCN

base --> KCN

now

another base NaOH is added

we know that

base will react with an acid

so

OH- + HCN ---> CN- + H20

we can see that

HCN is used up , so number of moles of HCN will decrease

CN- is being formed , so number of moles of CN- will increase.

A  false

B  false

C  false

D  true

E  false

chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances. these processes are called chemical reactions and, in general, are not reversible except by further chemical reactions. some reactions produce heat and are called exothermic reactions and others may require heat to enable the reaction to occur, which are called endothermic reactions. understanding chemical changes is a major part of the science of chemistry.