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


HCCOH

HClO4

HI

NH3

NaOH

HNO2

CH3COOH

(CH3)2NH

HNO3

Ca(OH)2

HCl

KOH

HCN

HF

CH3NH2

CsOH

HBr

LiOH

Ba(OH)2

H2SO4

Verified Answer :

Strong acids:
HCl
H₂SO₄
HI
HBr
HNO₃
HClO₄

Strong bases:
NaOH
Ca(OH)₂
KOH
CsOH
LiOH
Ba(OH)₂

Weak acids:
HF
HCN
CH₃COOH
HNO₂
HCOOH

Weak bases:
NH₃
(CH₃)₂NH
CH₃NH₂

Answer:

HCOOH  (formic acid)     weak acid

HClO₄                              strong acid

HI                                      strong acid

NH₃                                   weak base

NaOH                                strong base

HNO₂                                weak acid

CH₃COOH (acetic acid)   weak acid

(CH₃)₂NH                           weak base

HNO₃                                strong acid

Ca(OH)₂                            strong base

HCl                                     strong acid

KOH                                   strong base

HCN                                   weak acid

HF                                      weak acid

CH₃NH₂                             weak base

CsOH                                 strong base

HBr                                    strong acid

LiOH                                  strong base

Ba(OH)₂                            strong base

H₂SO₄                               strong acid

Explanation:

Strong electrolytes are those that completely dissociate in water, so they exist mostly in the ionic form.

AB(aq) ⇒ A⁺(aq) + B⁻(aq)

On the other hand, weak electrolytes dissociate only partially in water, so that at equilibrium there is a mixture of the molecular form and the ionic form.

AB(aq) ⇄ A⁺(aq) + B⁻(aq)

Electrolytes can be acid or basic.

There are 7 strong acids: HCl, HBr, HI, HClO₃, HClO₄, HNO₃ and H₂SO₄. The rest of the acids are weak.

Strong bases are those hydroxides that contain cation from Groups 1 and 2 of the Periodic Table (e.g. NaOH, Ca(OH)₂). The rest of the bases are weak.

NH₃
, (CH₃)₂NH, and CH₃NH₂ are bases, despite not having OH⁻ groups, because they can accept H⁺, according to Bronsted-Lowry acid-base definition.

NH₃ + H₂O ⇄ NH₄⁺ + OH⁻

(CH₃)₂NH + H₂O ⇄ (CH₃)₂NH₂⁺ + OH⁻

CH₃NH₂ + H₂O ⇄ CH₃NH₃⁺ + OH⁻

With this information, we can classify the compounds from the list as a strong acid, strong base, weak acid, or weak base.