Question

Consider a 0.150 M aqueous solution of HBrO where K_a(HBrO) = 2 × 10⁻⁹. TRUE/ FALSE

a. The pH of the solution is 4.76. (T)

b. There are 14 valence electrons in HBrO. (T)

c. When the solution is at equilibrium, adding KBrO would create more HBrO in solution. (T)

d. This solution would have no OH⁻ ions present. (F)

e. The strongest intermolecular forces between H₃O⁺ and H₂O are Hydrogen bonds. (F)

f. The conjugate base is BrO⁺. (F)

Please explain the answers.

Answer 1

Multiple choice

For 0.150 M HBrO,

a. HBrO + H2O <==> BrO- + H3O+

let x amount reacted,

Ka = [BrO-][H3O+]/[HBrO]

2 x 10^-9 = x^2/0.150

x = [H3O+] = 1.73 x 10^-5 M

pH = -log[H3O+] = 4.76

So,

pH of solution is 4.76 - True

b. there are 14 valence electrons in HBrO - True

total valence electrons = 1(H) + 7(Br) + 6(O) = 14 electrons

c. when the solution is at equlibrium, adding KBrOwould create more HBrO in the solution - True

This is according to the LeChatelier's principle, which states that If any change occurs in a reaction at equilibrium, the reaction would shift to that direction so as to minimize the change occured an dreschieve the equilibrium state.

So adding KBrO would increase concentration of BrO- in solution, which would push reaction towards reactant side and more of HBrO would be formed.

d. The solution would have no OH- present - False

OH- would be formed by hydrolysis of conjugate base BrO- in solution,

BrO- + H2O <==> HBrO + OH-

e. The strongest intermolecular force between H3O+ and H2O are hydrogen bonds - True

f. The conjugate base is BrO+ - False

Conjugate base is BrO-