Page 283 - Chemistry

Observation Inference
- Effervescence/ fizzling/bubbles of a Presence of – COOH/ H /H 3O ions.
+
+
colourless gas. Solution is acid . (1 mk)
(ii)
- No effect on litmus paper.
Observation Inference
- The solution remained orange. - Absence of R-OH. (1 mk)

(iii)
Observation Inference

Solution turns from purple to colourless - Presence of of –C C-
solution is decolourised (1 mk)

SOIK DISTRICT

1. TABLE I
a)Complete table penalize ½ for inverted table and arithmetic errors
nd
st
b) Use of decimal tied to the 1 and 2 rows
½
c) Accuracy ±0.2 s.v √ ± 0.1 sv√1
d) Principles of averaging as shown below
e) Final answer ± 0.2s.v ± 0.1 s.v√1

a)T 1+T 2+T 3√
½
3
½
= correct answer√ (2d.place) (transferred to the table)
b)i) 5 √
½
40
=0.125 moles per litre
½
ii)COOHCOOH (aq) + 2 NaH (aq) COONaCOONa (aq) +2H 2O (l) √ balanced
½
√ s.symbols
OR
C 2H 2O 4(aq) +2 Na 2O 4(aq) +C 2Na 2O 4(aq) 2H 2O(l)

iii) Moles of NaOH = 25X0.125 √
1000
= 0.003125
Moles of C 2H 2O 4 = 0.003125 X 1
2
= 0.0015625
Ans in (a) 0.00015625

3
1000cm 1000x0.0015625 √
½
Ans in (a)
= Correct answer √
½
V) C 2H 2O 4 X H 2O = answer in (iv) √
½

18x = Ans (iv) - 90√
½
x = Ans (iv) – 90 √
½
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