Practice Gk questions set 2 - general science mcq Online Quiz (set-1) For All Competitive Exams
Q-1) Which of the following does not corrode when exposed to the atmosphere?
(a)
(b)
(c)
(d)
Gold is a noble metal.
Q-2) Rusting of an iron is an example of
(a)
(b)
(c)
(d)
Rusting results in formation of iron oxide.
Q-3) The empirical formula of a compound is CH2 . One mole of this compound has a mass of 42 grams. Its molecular formula is :
(a)
(b)
(c)
(d)
Empirical formula of compound = $CH_2$ Molecular mass of the compound = 42 ∴ n = $42/14$ = 3 ∴ Hence molecular formula = $C_3H_6$
Q-4) When electrons are added the resulting ion is called
(a)
(b)
(c)
(d)
Cl + e– Cl– (acidic radicals)
Q-5) 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)
(b)
(c)
(d)
As the sum of the percentage of C, H & N is 100. Thus it does not contains O atom.
Table for empirical formula
| Element | % | At. Wt. | Rel.Number | Ratio | ||||
| C | 40.00 | 12 | $40/12$= 3.66 | ${3.66}/{3.33}=1.09 ∼ 1$ | ||||
| H | 13.33 | 1 | ${13.33}/1$= 13.33 | ${13.33}/{3.33}=4$ | ||||
| N | 46.67 | 14 | ${46.67}/14$= 3.33 | ${3.33}/{3.33}=1$ |
Q-6) The branch of chemistry which deals with study of physical properties and conditions is
(a)
(b)
(c)
(d)
Q-7) Which of the following is most unreactive ?
(a)
(b)
(c)
(d)
Mg++ (12 – 2 = 10e– ) = 2, 8
Hence have complete octel hence inert.
Q-8) The observation that does not indicate a chemical reaction is
(a)
(b)
(c)
(d)
A chemical reaction is generally accompanied by a change of temperature, colour or evolution of a gas.
Q-9) Which one of the following is not an exothermic reaction ?
(a)
(b)
(c)
(d)
No reaction occurs in this case.
Q-10) AgNO3(aq) + NaCl(aq) ⟶ AgCl(s) + NaNO3(aq) Above reaction is -
(a)
(b)
(c)
(d)
This reaction is double displacement and precipitation as well because insoluble silver chloride gets precipitated.