Post Utme Chemistry Past Questions and Answers

Question 1046:

An amount of \(1.0 \times 10^{-3}\) moles of \(Ag ^{+}\)and \(1.0 \times 10^{-3}\) of \(CrO _{4}^{2-}\) react together to form solid \(Ag _{2} CrO _{4}\). What is the amount of \(Ag _{2} CrO _{4}\) formed.
\([ Ag =108, Cr =52, O =16]\).

A. 0.33 g
B. 0 .67 g
C. \(3.52 g\)
D. \(0.166 g\)

Question 1047:

A mole of a compound contains \(54 g\) of \(Al\) atoms, \(1.806\) \(\times 10^{24}\) of Sulphur atoms and \(192 g\) of oxygen atoms. The molecular formula of the compound is?
[ \(Al =27, S =32\), \(\left.O =16, N _{ A }=6.02 \times 10^{23}\right]\)

A. \(AlSO _{3}\)
B. \(Al _{2} S _{2} O _{2}\)
C. \(Al _{2} SO _{2} \)
D. \(Al _{2}\left( SO _{4}\right)_{3}\)

Question 1048:

The central atom of which of the following molecules is/ are sp \(^{3}\) hybridized prior to bonding?
i. \(CO _{2}\) ii. \(NH _{3}\) iii. \(BeCl _{2}\) iv. \(H _{2} O\) v. \(CH _{4}\)

A. Ii, iv & v
B. I, iii, iv
C. Ii, iii, iv
D. I, ii, iii

Question 1049:

Arange the elements aluminium, silicon, phosphorus \& Sulphur in order of increasing first ionization energy

A. \(Al < Si < P < S\)
B. \(P < S < Si < Al\)
C. \(Al < Si < S < P\)
D. \(S < Si < P < Al \)

Question 1050:

Which of the following metals are passive to hot concentrated \(H _{2} SO _{4}\) ?
i. \(Au\) ii. \(Ag\) iii. \(Pt\) iv. \(Ca\)

A. I & ii
B. Ii & iii
C. iii & iv
C. I & iii