X-ICSE
CHEMISTRY
Section-I
- (A) I). nitric oxide , steam and energy
ii) Merquery
iii)Alkanol
iv) Ammonium nitrate --------> Nitrous oxide +Steam
v) Aqua regia
(b) i) 1. F < Cl < Br < I< At
2. I < Br < Cl < F
ii) Mg and Mn
iii) Vanadium pentaoxide or platinum
( c) 2H S + 3 O -----------> 2 H O + 2 SO
68 gm 96 gm 36 gm 128 gm
As 128 gm sulphur dioxide yields by burning of 68 gm hydrogen sulphide
So 12.8 gm sulphur dioxide yields by burning of = 68 X 12.8 / 128
= 6.8 gm hydrogen sulphide
As 128 gm sulphur dioxide occupies volume =22.4 l at S.T.P.
So 12.8 gm sulphur dioxide occupies volume =22.4 X 12.8/128 l at S.T.P
=2.24 l at S.T.P
(d) (i) Dil.Sulphuric acid
(ii) Dil. Nitric acid
(iii) 1. Zn + HCl ---------> ZnCl2 + H2
- 2 NaOH + H2So4 ----------> Na2SO4 + 2H2O
- CuO + 4HNO3 --------> Cu ( NO3) + 2NO2 + 2H2O
(e)
(f)(i) Na2SO3 + 2 HCl -------------> 2 NaCl + H2o + So2
(ii) 2NH3 + 3CuO --------> 3Cu + 3H2O + N2
(iii) CuSO4 + 5H2O ----------> CuSO4.5H2O
(iv) C6H12 O6 --------> 6C + 6H2O
(v) AgNo3 + 2NaCl ----------> AgCl2 + NaNO3
(g) (i) Fe + H2SO4 ---------->FeSO4 + H2
(ii) Cu + Con. 4HNO3 -----------> Cu( NO3) + 2H2O + 2NO2
(iii) H2S + H2SO4 -------------> S + 2H2O + SO2
(iv) Cl2 + So2 + H2O --------------> 2HCl + H2SO4
(v) C2H2 + 2AgNO3 + 2NH4OH -----------> Ag-cc-Ag + 2NH4NO3 + 2H2O
(h) (i) Li
(ii) F
(iii) F
(iv) Li ,Na , K
(v) Greater as no. of shells increases
Section-II
Ans-2 (a)
| Element | % Composition | At. Wt. | Relative no. of Atoms | Simplest Ratio |
| C | 85.7 | 12 | 85.7/12=7.14 | 7.14/7.14=1 |
| H | 14.3 | 1 | 14.3/1=14.3 | 14.3/7.14=2 |
Emperical Formula= CH2
(b) molecular mass of E.F.= 12+ 2 =14
Relative molecular mass = 28
, n= 28/14 =2
Molecular formula= (CH2)2
= C2H4
( c) Acetylene
( d) Double bond
( e) Substitution reaction
( f) C2H4 + H2 ----------> C2H6
Ans-3 . Nitric Acid -1. purification of gold
2. Preparation of fertilizers
ii) Ammonia – 1. As cleaning agent
2. Refrigerant in ice plants
iii) Hydrochloric acid- 1. Extraction of glue from bones
2. Preparation of aqua regia
(b) (i) 2Al + 3 H2so4 ---------------> Al2 (SO4)3 + 3H2 + SO2
(ii) Al2O3 . 2H2 O + 2 NaOH ------------> 2 NaAlO2 + 3H2O
NaAlO2 + 2H2O -------------> NaOH + Al( OH) 3
2Al(OH)3 -------------> Al2O3 + 3H2O
Ans-4 (a) (i) With BaCl2 H2SO4 gives ppt. but HCl not.
(ii) Metals in general allow an electric current to flow through them and are called conductrors of electricity. While compounds which conduct electricity when dissolved in water are called electrolyte.
(iii) H2C=CH2 + H2 ---------> H3C-CH3 ( Ni catalyst)
(iv) Polar
(b) (i) It is poisonous gas can cause death also.
(ii) 2Mg + SO2 ----------> 2MgO +S
2H2S + SO2 -----------> 3S + 2H2O
(iii) Ammonium carbonate
Ans-5 (a) (i) FeCl3 + 3NH4OH ------------> 3NH4Cl + Fe(OH)3
Reddish brown
(ii) 2 NH3 + CO2 ----------> NH2.CO.NH2 + H2O
(iii) Gives sulphite or bisulphate salt and water
(iv) 2HBr + H2SO4 -----------> Br2 + 2H2O + SO2
(b) (i) Sodium chloride contains ionic bond while carbon tetrachloride is covalent.
(ii) The reaction is slow and negligible in bthe dark.
(iii) As very weak metal in activity series.
Ans-6 (a) (i) As 31 gm P gives 98 gm phosphoric acid
So 12. 4 gm gives 98 X 12.4 / 31= 39.2 gm
(ii) 5 HNO3
5[ 1+ 14 + 3X 16 ]
5 [ 1+ 14 + 48]
5 X 63 = 315 gm
(b)(i) 4NH3 + 5 O2 --------------> 4NO + 6 H2O + ∆ ( Catalyst Pt, Temp. 800◦c)
(ii) 2NH3 + 3CuO -----------------> 3Cu + 3H2O + N2
( c)(i) With ethene it is addition reaction but with ethane it is substitution reaction.
(ii) Addition reaction
(iii) Dichloro ethane
Ans-7 (a) (i) Aluminium
(ii) CAthoder
(iii) Electro –refining
(iv) Ammonia
(v) Ammonia
(b) (i)1. Methan-al
2. Ethanoic acid
3. Chloro ethane
4. Ethene
(ii) 1. CH3 COONa + NaOH ---------------> CH4 + Na2CO3 ( in the presence of CaO )
2. CH4 -------------> CH3OH ( Oxidising agent K2Cr2O7)
3. CH2Cl2 + Cl2 --------------> CHCl3 + HCl
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