Waec 2023 Chemistry Practical Question And Answer Now Available.

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(2a)
TEST; C + distilled water + shake

OBSERVATIONS; It dissolves to give a colourless or clear solution

INFERENCE; Soluble salt suspected

(2ai)
TEST; Solution C + litmus paper

OBSERVATIONS; It has no effect on both blue and red litmus paper

INFERENCE; Neutral solution

(2aii)
TEST; solution C + Fehling solution A and B + heat

OBSERVATIONS; It gives a black red colour

INFERENCE; Reading agent confirmed

(2bi)
TEST; D + heat

OBSERVATIONS; It turns yellow on heating and white on cooling

INFERENCE; ZnO is present

(2bii)
TEST; D + dilute Hcl + heat

OBSERVATIONS; It dissolves completely to give a clear or colourless solution

INFERENCE; Solution chlorides of Zn³+, Al³+ is present

(2biii)
TEST; Solution D + NaOH in drops and then in excess

OBSERVATIONS; It gives white gelatinous precipitate. The precipitate is soluble in excess.

INFERENCE; Al³+, Zn²+ present.
Al³+, Zn²+ present .

(2biv)
TEST; Solution D + NH3 in drops and then in excess

OBSERVATIONS; It gives white gelatinous precipitate. The precipitate is soluble in excess NH3

INFERENCE; Al³+, Zn²+ is present.
Zn²+ confirmed.

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