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

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.

answer: c. the experiment shows that the red substance experienced a chemical change.

explanation: chemical change is the change in which chemical composition of the substance changes. physical change is the change in which there is no change in chemical composition.

chemical changes are accompanied by following changes:

a) precipitate formation

b) energy is released or absorbed

c) formation of bubbles

d) change in color

as it is given that the red color has disappeared and there is production of gas, it means the red substance has undergone a chemical change.

e