An organic compound made of C, H and N contains 20% nitrogen. Its molecular weight is:
A. 70 B. 140 C. 100 D. 65 Solution: (A) The atomic mass of nitrogen = 14 Since the compound... View Article
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In an experiment, 4 gm of M2Ox oxide was reduced to 2.8 gm of the metal. If the atomic mass of the metal is 56 gm/mol, the number of oxygen atoms in the oxide is:
A. 1 B. 2 C. 3 D. 4 Solution: (C) 1 Mol M2Ox = (2 x 56 + 16 x)... View Article
If the components of air are N2 78%, O2 21%; Ar 0.9% and CO2 0.1% by volume, what will be the molecular weight of air?
A. 28.9 B. 32.4 C. 16.4 D. 14.5 Solution: (A) Avg molar mass of air = (28×78+32×21+40×0.9+44×0.1) / 100 =... View Article
An organic compound containing C, H and N gave the following analysis: C = 40%; H = 13.33%; N = 46.67%. Its empirical formula would be;
A. C2H2N B. C3H7N C. CH4N D. CHN Solution: (C) Element % by mass Atomic mass Relative number of moles... View Article
A compound contains two oxygen atoms, four carbon atoms and the number of hydrogen atoms is double of carbon atoms. What is the density of vapour of this compound?
A. 88 B. 44 C. 132 D. 72 Solution: (B) M.F. C4H8O2 The compound contains two oxygen atoms, four carbon... View Article
Calculate the amount of NaOH required to neutralize 100 mL 0.1 M H2SO4.
A. 40 g B. 0.4 g C. 80 g D. 0.8 g Solution: (D) 0.1 M H2SO4 = 1000 mL... View Article
How much calcium oxide (CaO) can be obtained by heating 200 Kg of limestone that is 95% pure CaCO3?
A. 104.4 kg B. 105.4 kg C. 212.8 kg D. 106.4 kg Solution: (D) Considering 100 kg impure sample has... View Article
Percentage of Se in peroxidase anhydrous enzyme is 0.5% by weight (at. wt. = 78.4) then minimum molecular weight of peroxidase anhydrous enzyme is:
A. 1.568 x 104 B. 1.568 x 103 C. 15.68 D. 2.136 x 104 Solution: (A) In peroxidase anhydrous enzyme... View Article
Impure sample of ZnS contains 42.34% Zn. What is the percentage of pure ZnS in the smaple?
A. 67% B. 63% C. 58% D. 37% Solution: (B) The percentage of pure ZnS in the sample is 63%.
What weight of CuO will be required to provide 200 Kg copper?
A. 200 kg B. 79.5 kg C. 250 kg D. 100 kg Solution: (C) CuO ⟶ 2Cu + O2 Mass... View Article
In which of the following pairs percent compostion of element is not same?
A. Benzene and Ethyne B. But – 2 – ene and Cyclobutane C. Glucose and Fructose D. Phenol and Ethanol... View Article
At STP, the density of CCl4 vapour in g/L will be nearest to;
A. 6.87 B. 3.42 C. 10.26 D. 4.57 Solution: (A) As per Avogadro’s law, 1 mole of every substance will... View Article
What is the normality of 0.3 M phosphorous acid:
A. 0.1 B. 0.9 C. 0.3 D. 0.6 Solution: (D) Phosphorous acid is a type of an ibasic acid because... View Article
Boron has two stable isotopes, 10B(19%) and 11B(81%). Calculate the average atomic weight of boron in the periodic table.
A. 10.8 B. 10.2 C. 11.2 D. 10.0 Solution: (B) Average atomic weight = ∑% abundant × atomic mass /... View Article
The molecular weight of O2 and SO2 are 32 and 64 respectively. At 15°C and 150 mmHg pressure! one litre of O2 contains ‘N’ molecules. The number of molecules in two litres of SO2 under the same conditions of temperature and pressure will be:
A. N/2 B. N C. 2N D. 4N Solution: (C) If we recall Avogadro’s law it states, equal volumes of... View Article
The same amount of Zinc is treated separately with an excess sulphuric acid and excess sodium hydroxide. What will be the ratio of volumes of hydrogen evolved?
A. 1 : 1 B. 1 : 2 C. 2 : 1 D. 9 : 4 Solution: (A) Zinc reacts... View Article
The number of oxygen atoms in 4.4 g of CO2 is
A. 1.2 x 1023 B. 6 x 1022 C. 6 x 1023 D. 12 x 1023 Solution: (A) Moles of... View Article
How many significant digits are there in 0.25?
A. 1 B. 2 C. 3 D. Cannot be determined Solution: (B) The number 0.20 is precise to 2 significant... View Article
Volume occupied by one molecule of water (density 1 g cm-3) is:
A. 3.0 × 10-23 cm3 B. 5.5 × 10-23 cm3 C. 9.0 × 10-23 cm3 D. 6.023 × 10-23 cm3... View Article
The drug which is used for treating AIDS victims is;
A. Azidothymidine B. Cis-platin C. Taxol D. All of them Solution: (A) Azidothymidine (AZT) which is a type of antiretroviral... View Article
