Chemistry Past Questions and Answers

NH₃ + H₃O⁺
â†’ NH₄⁺ + H₂O. It may be deduced from the reaction above that?

A A redox reaction has occurred
B H₃O⁺ acts as an oxidizing agent
C H₃O⁺ acts as an acid
D Water acts as ab acid

Question 17:

4.0 g of sodium hydroxide in 250 cm³ of solution contains?

A 0.40 moles per dm³
B 0.10 moles per dm³
C 0.04 moles per dm³
D 0.02 moles per dm³

Question 18:

During the electrolysis of a salt of a metal M, a current of 0.5 A flows from for 32 minutes 10 seconds and deposits 0.325 g of M, What is the charge of the metal ion?
(M = 65, If = 96,500 C per mole of electron)

Question 19:

Which of the reactions occurs at the anode during the electrolysis of a very dilute aqueous solution of sodium chloride?

A OH^- - e â†’ OH
B CIsup>- - e → CI
C OHsup>- + CIsup>-HCI + O₂
D Na₊ - esup>- Hg (Na)/(Hg) amalgam

Question 20:

The oxidation states of chlorine in HOCL, HCLO₃ and HCLO₄ are respectively?

A -1, +5, and +7
B -1, -5 and 7
C +1, +3 and +4
D +1, +5 and +7