DeXtEr (1a)
(i)
- BURETE READING: Rough, 1st, 2nd, 3rd
- FINAL READING: 31.00, 29.50, 33.15, 31.50
- INITIAL READING: 2.50, 1.45, 4.40, 3.40 - VOL OF A USED: 33.50, 28.05, 28.75, 28.10
(ii)
Average Volume of Acid Used = 28.05+28.75+28.10/3
= 84.90/3
= 28.30cm^3

(iii)
Molar mass of YOH = conc. Of YOH solution
mgdm^-3/conc. Of YOH solution in moldm-3 = 7.00/0.126145
= 55.5
YOH = 56, Y + 17
= 56
Y = 56-17
Y=39
(IV) The element Y is potassium
© - Do not use more than 3 drop of indicator
- Use a white tile
- Shake the conical flask thoroughly during the titration
- Avoid running in the acid at a very fast rate

(2a) Observation
(I) D dissolved completely in water to give a colorless solution
(ii) Release of a colorless gas which turns lime water milky
(iii) Dissolved in water to give brownish solution which turn red litmus paper blue
(iv) Green solution obtained
(v) Double decomposition reaction
(Bi)
X = Ammonia ( NH3)
Y = Ammonium chloride (NHiCl) Z = Nitrogen (N) oxide (NO2)
©
(i) Pb(NO3)2(aq) + H2^3(g) ===> pbs + H20 + NO2
Black colour of pbs obtained and release of No2
(ii) K2CrO7 + SO2 + H2SO4 ===> K2SO4 + cr2(SO4)3
+ H20 SO2 changes orange color of K2Cr207 solution to a
clear green solution Cr2(SO4)
(3ai)
I - Delivery tube
II - Combustion tube
III - Beaker
IV - Collecting tube
(ii) W is hydrogen gas
(iii) The gas W gives a pop sound with lighted splinter
(Iv) CUO + H2 ---> CU + H20 (1) From black to blue
(2) Formation of water obtained
(b)
(i) Downward delivery I.e upward displaced cement by air
(ii) I. Decolourisation (from purple to colorless) II. Reddish - brown ppt obtained
© Tabulate
* Test = Glucose + Fehling solution + boiling
* Observation = A yellow ppt obtained