Classify each substance as a strong acid, strong base, weak acid, or weak base.

Question

Classify each substance as a strong acid, strong base, weak acid, or weak base.

Ba(OH)2, Ca(OH)2, HCN, HNO3, (CH3)2NH, H2SO4, HCI, HCOOH, CH3COOH, HI, HF, Sr(OH)2, KOH, NH3

Part B

Determine whether the following hydroxide ion concentrations ([OH] ) correspond to acidic, basic, or neutral solutions by estimating their corresponding hydronium ion concentrations ([H3O+] using the ion product constant of water (Kw ).

It may help to keep the following equation in mind as you work

Kw = [H3O+][OH] = [1×107 M][1×107 M] = 1×1014 M

[OH-]=4x10-12 M, [OH-]=3x10-9 M, [OH-]=8x10-10 M, [OH-]=4x10-13 M, [OH-]=4x10-2 M, [OH-]=8x10-4 M, [OH-]=6x10-5 M, [OH-]=1x10-7 M,

Explanation / Answer

(A) Strong acid is the one which undergoes complete ionisation to give H+ ions and strong base is the one which undergoes complete ionisation to give OH- ions.

Ba(OH)2 Strong base

Ca(OH)2 Strong base

HCN Weak acid

HNO3 Strong acid

(CH3)2NH Weak base

H2SO4 strong acid

HCI strong acid

HCOOH weak acid

CH3COOH weak acid

HI strong acid

HF weak acid

Sr(OH)2 strong base

KOH strong base

NH3 weak base

(B)

[OH-]=4x10-12 M acidic ([H3O+] = 1.0 * 10-14 / (4. * 10-12) = 2.5 * 10-3 M > 1.0 * 10-7, hence acidic)

[OH-]=3x10-9 M Acidic

[OH-]=8x10-10 M Acidic

[OH-]=4x10-13 M Acidic

[OH-]=4x10-2 M Basic

[OH-]=8x10-4 M Basic

[OH-]=6x10-5 M Basic

[OH-]=1x10-7 M Neutral

Related Questions

Navigate

• Browse (All)
• Browse C
• Subjects