Chemistry Past Questions and Answers

An aqueous solution of a metal salt, M. gives a white precipitate with NaOH which dissolves in excess NaOH. With aqueous ammonia, the solution of M also gives a white precipitate which dissolves in excess ammonia Therefore the cation in M is

A Zn
B Ca
C Al
D Po

Question 32:

What is the concentration of a solution containing 2g of NaOH in 100cm3 of solution? [Na = 23, O =16, H = 1]

A 0.40 moldm\(^{-3}\)
B 0.50 moldm\(^{-3}\)
C 0.05 moldm\(^{-3}\)
D 0.30 moldm\(^{-3}\)

Question 33:

How many atoms are present in 6.0g of magnesium? [Mg = 24, N.A = 6.02 x 10 \(^{23}\)mol]

A 1.20 x 10\(^{22}\)
B 2.4 x 10\(^{22}\)
C 1.51 x 10\(^{22}\)
D 3.02 x 10\(^{22}\)

Question 34:

The radio isotope used in industrial radiography for the rapid checking of faults in welds and casting is?

A Carbon-14
B Phosphorus-32
C Cobalt
D Iodine-131

Question 35:

Beryllium and Aluminium have similar properties because they

A Are both metals
B Belong to the same group
C Belong to the same period
D Are positioned diagonally to each other