1.  Which of the following species is the reducing agent?

2 CuBr 2Cu + Br2

Cu
CuBr
Cu+
Br-
Br2

2. Which of the following statements is untrue about oxidation and reduction processes?

An oxidation can happen without a reduction.

It involves the exchange of electrons.

Often ions are generated or consumed.

Electrons are often involved in oxidation and reduction reactions.

All of these are true.

3. What would be the best explanation for the fact that most natural water has a pH of about 5.6?

Carbon dioxide reacts with water to form an acid.

Air contains acid rain particles.

Minerals that are dissolved in water are often acidic.

Many salts that dissolve in natural waters make the water basic.

None of these

4. Hydrogen chloride is added to a buffer solution of ammonia, NH3, and ammonium chloride, NH4 Cl . What is the effect on the concentration of ammonia? What is the effect on the concentration of ammonium chloride?

HCl reacts with both the ammonia and ammonium chloride, so the concentration of both decreases.

HCl reacts with only the ammonium chloride, so the concentration of the ammonium chloride decreases and the concentration of ammonia increases.

HCl reacts with both the ammonia and ammonium chloride, so the concentration of both increases.

HCl reacts with only the ammonia, so the concentration of the ammonium chloride increases and the concentration of ammonia decreases.

Attachment:- Quiz 4.docx