1 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
SOLUTION
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
2
Schizont stage in the life cycle of malarial parasite occurs in1. Erythrocytes of man2. Stomach of Anopheles3. Blood of man4. Salivary glands of Anopheles
3 Solutions
0.2 g of an organic compound gave 0.17 g NH3? in kjeldhal's method. The percentage weight of nitrogen in the given compound is:
1) 70% 2) 80% 3) 50% 4) 90%
The molar mass of NH3? is 17 g/mol. The atomic mass of N is 14 g/mol. 0.2 g of an organic compound gave 0.17 g NH3? in kjeldhal's method. The percentage weight of nitrogen in the given compound is (14 /17) ?× (0.17 / 0.2)?×100=70 %
4
Origin of species was published in the year 1) 1859 2) 1862 3) 1883 4) 1919
5
Waste produces of adenine and guanine metabolism are excreted by man as1. Ammonia2. Urea3. Uric acid4. Allantion
6
The gymnosperms and angiosperms differ from the rest of the vascular plants in that :1) they have an independent gametophyte generation2) they have flagellated sperm3) they are herterosporous4) embryo development occurs with in the female gametophyte
7 Cell -The Unit of Life
Glycoproteins are known to play an important role in cell recognition, the specificity of this recognition is largely provided by
1) Lipid portion of glycoproteins 2) Protein portion of glycoproteins 3) Carbohydrate portion of glycoproteins 4) Both carbohydrate and protein components of glycoproteins
Carbohydrates are attached to the extracellular face of the plasma membrane in the form of glycoproteins attached to intrinsic or peripheral proteins. These majorly act as receptors for various signalling compounds. Example- antigens present on the surface of RBC are glycoproteins
8 Electronic Devices
If rp = 3 x 103 ohm and gm = 20 m. mho if triode is used as an amplifier and RL = 6 kohm, then voltage amplification is
(1) 40 (2) 60 (3) 20 (4) 30
9 Stoichiometry
Zinc sulphate contains 22.65% of zinc and 43.9% of water of crystallization. If the law of constant proportions is true, then the weight of zinc required to produce 20g of the crystals will be
1) 45.3g 2) 4.53g 3) 0.453g 4) 453g
100g of crystals are obtained from =22.65g of Zn
∴ 20g of crystals are obtained from =22.65 ×20/ 100
⇒ 4.53g
10
The head cap of a sperm is called 1. centrosome 2. acrosome 3. lysosome 4. none of the these
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