1 States of Matter
The compressibility factor of gas is more than unity at STP. Its value of Vm is 1) Equal to 22.4 dm3 2) Dependent on its molecular size 3) Greater than 22.4 dm3 4) lesser than 22.4dm3
SOLUTION
We know that Z=V(real)/ V(ideal) Since Z > 1, it means V(real) > V(ideal) At STP, V(ideal)=22.4 L=22.4 dm3 Hence, V(real) > 22.4 dm3
2 P – Block Elements
In the manufacture of nitric acid by ostwald,s process, the catalyst used are 1) finely divided iron 2) Pt-Rn gauze 3) vanadium pantoxide 4) molybdenum
3 Chemical Equilibrium
At equilibrium 500ml500ml vessel contains 1.5M of each A,B,C,D if 0.5N if C and D expelled out than what would be the Kc ? 1) 1 2) 1/9 3) 4/9 4) 5/9
A+B=C+D
Intially,[A]=[B]=[C]=[D]= M
Now change in [C]= change in [D]= M
Hence, remaining [C]=[D]=1.5 M−0.5 M=1.0 M
$$K=\frac{[C][D]}{[A][B]}$$
= 4/9
4 Aldehydes Ketones and Carboxylic Acids
Which of the following will form when calcium acetate is distilled?
1) Formaldehyde
2) Ethanal
3) Propanal
4) Acetone
5 Electrochemistry
E0(Ni2+/Ni)=−0.25volt, E0(Au3+/Au)=1.50volt . The standard emf of the voltaic cell. Ni(s)|Ni2+(aq)(1.0M)|| Au3+(aq)(1.0M)|Au(s)Ni(s)|Ni(aq)2+(1.0M)||Au(aq)3+(1.0M)|Au(s) is: 1) 1.25 volt 2) - 1.75 volt 3) 1.75 volt 4) 4.0 volt
E0cell=(E0Ni/Ni2++E0Au3+/Au)
=(0.25+1.50)=1.75volt
6 Chemistry in Everyday Life
The compound used as a preservative for food products such as tomato ketchup and fruit juices is
1) Sodium benzoate 2) Formic acid 3) Sodium Salicylate 4) Sodium acetate.
7 Hydrocarbons
An alkyl bromide, RBr of molecular weight 151 is the exclusive product of bromination of which hydrocarbon?
1) Dodecane 2) 2,2 - dimethylpropane 3) 2,2 - dimethylhexane 4) 2,2,3 - trimethylheptane
Molecular weight of RBr=151
Molecular weight of Br=80
∴ Molecular weight of −R=151−80=71
If we consider 2,2−dimethylpropane the molecular formula is C5H12 .
After bromination, C5H11Br
∴ Molecular weight of C5H11=60+11=71
8 S – Block Elements
For which of the following crystalline substances does the solubility in water increase upto 32? and then decrease rapidly?
1) CaCl2.2H2O 2) Na2SO4.10H2O 3) FeSO4.7H2O 4) Alums
9 Classification of Elements and Periodicity
The correct order of decreasing ionic radius among the following anions would be: 1) Se2−,I−,Br−,F−,O2− 2) F−.Br−,O2−,Se2−,I− 3) I−,Se2−,Br−,O2−,F− 4) F−,O2−,Br−,Se2−,I−
The correct order of decreasing ionic radius among the following anions would be I−,Se2−,Br−,O2−,F−
On moving down the group, the ionic radii increases as new shells of electrons are added. The radius of the isoelectronic species decreases with increasing charge.
10 Hydrogen
In which of the compounds does hydrogen have an oxidation state of - 1?
1) CaH2
2) HCl
3) NH3
4) CH4
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