Question 2
- (i)Define the term functional group.;
(ii)Consider the following compound:
State the:
I. functional group:
II. name of the compound. [4 marks] -
(i)Name the class of organic compounds that could be identified using each of the following reagents
I. acidified tetraoxomanganate (VII) solution;
II. ethanoic acid and conc. tetraoxosulphate (VI) acid;
III. sodium trioxocarbonate (IV) solution.
(ii) State what is observed in each of the tests in 2(b)(i). [6 marks] - (i) Consider the following reaction equation:
State the oxidation number of chlorine:
I. before the reaction;
II. after the reaction.
(ii) A ring is to be gold-plated by electrolysis using Au(NO3)3 solution.
I. Write the reaction at the cathode.
II. Calculate the time required to deposit 0.50 g gold on the ring when a current of 0.8 A is passed through the electrolyte.
[Au = 197, 1 F = 96500 C] [10 marks] - Consider an ion with the symbol X2+ formed from its elemental state.
(i) Which group does X belong in the periodic table?
(ii) What is the formula of the compound formed from X2+ and a nitride ion?
(iii) If X is in period 2, identify X.
Observation
This was not a popular question among the candidates.
In part (a), majority of the candidates could not identify the functional group present in the compound, majority of them did not know that esters are called alkylalkanoates.
In part (b), majority of the candidates could name the class of organic compounds that could be identified using each of the listed reagents..
In part (c), majority of the candidates answered this question. However, some of them did not know that chlorine could exhibit two different oxidation states in chemical reactions..
In part (d), majority of the candidates could not associate X to beryllium if X is in period 2.