Trioxonitrate (V) acid is not used for preparing hydrogen gas from metals because it

A. is strongly oxidizing

B. is volatile

C. renders the metal passive

D. forms a layer of oxide on the metal

An element used in the production of matches is

A. nitrogen

B. aluminium

C. copper

D. sulphur

When calcium oxide is heated with carbon, the oxide will

A. be converted to carbide

B. be converted to the trioxocarbonate (IV) salt

C. decompose to the metal

D. melt,producingg carbon (IV) oxide

A solution which on treatment with hydrochloric acid produces a colourless, odourless gas which turns lime water milky is most likely to be a

A. trioxonitrate (V)

B. chloride

C. trioxocarbonate (IV)

D. hydroxide

The soft solder used for welding and plumbing is alloy of

A. lead and tin

B. iron and tin

C. lead and zinc

D. iron and zinc

The reddish-brown rust on iron roofing sheets consists of

A. Fe³⁺(H₂O)₆

B. FeO.H₂O

C. Fe₂O₃.3H₂O

D. Fe₃O₄.2H₂O

Na₂S₂O_3(aq) + 2HCl_(aq) → 2NaCl_(aq) + H₂O_(l)
Which of the following would introduce the greatest increase in the rate of the chemical reaction above?

A. An increase in temperature and decrease in the concentration of the reactant

B. A decrease in the volume and increase in the pressure of the reactant

C. A decrease in the temperature and an incease in the concentration of the reactant

D. An increase in temperature and an increase in the concentration of the reactant

The tincture of iodine means iodine dissolved in

A. ethanol

B. bromine chloride

C. chlorine water

D. water

Cu2+(aq) + 4NH3(g) ↔ [Cu(NH3)4]2+(aq)
In the reaction above, what is the effect of precipitating Cu2+(aq) as CuS(s)?

A. NH_3(g) concentration will decrease

B. more NH_3(g)

C. The equilibrium will shift to the right

D. There will be no effect

Copper and silver metals are commonly use as coin because they are

A. easily reduced

B. not easily reduced

C. easily oxidized

D. not easily oxidized