Chemistry Questions & Answers - Free Online Practice

526.

If 0.2g of a salt is required to saturate 200 $cm^{3}$ of water at room temperature, what is the solubility of the salt?

0.2 $gdm^{-3}$

1.0 $gdm^{-3}$

2.0 $gdm^{-3}$

5.0 $gdm^{-3}$

View answer & explanation

Correct answer is B

Solubility in $gdm^{-3}$ = $\frac{mass of salt in gram}{volume of liquid in dm^{3}}$

200 $cm^{3}$ = $\frac{200}{1000} dm^{3} = 0.2dm^{3}$

Solubility = $\frac{0.2g}{0.2dm^{3}}$

= 1.0 $gdm^{-3}$

527.

Solubility curve can be used in the determination of the

amount of crystals formed

amount of solvent that can be recovered

amount of solid drugs in a given solution

temperature of the solution

View answer & explanation

Correct answer is C

No explanation has been provided for this answer.

528.

When water was added to a white anhydrous substance X, the colour changed to blue. X is

$CuSO_{4}$

$FeSO_{4}$

$Na_{2}SO_{4}$

$PbSO_{4}$

View answer & explanation

Correct answer is A

When water is added to white coloured anhydrous copper sulphate, its colour changes to blue, indicating that the blue coloured copper sulphate pentahydrate is regenerated.

529.

Potassium Chloride solid does not conduct electricity because

it is a covalent compound

strong cohesive forces make its ions immobile

strong cohesive force makes its molecule immobile

each of potassium and chlorine structures contain noble gas structure

View answer & explanation

Correct answer is B

For a substance to conduct electricity, it must have charge particles like electrons and ions within it that are able to move freely throughout it. In its solid state, potassium chloride (like many other ionic compounds) have fixed ions, hence, they are immobile and can't conduct electricity.

530.

Halogens generally react with metals to form

alkalis

acids

bases

salts

View answer & explanation

Correct answer is D

The word "halogen" is a Greek word meaning salt former, because they form salts when they react with metals eg NaCl.