The oxidation number of sulphur in S8,S2F2,H2S
respectively, are
Trả lời
(A)
0, +1 and -2
2
The normality of 0.3 M phosphorus acid (H3PO3) is
Trả lời
(D)
0.6
3
How many millilitres of 0.5 M H2SO4 are needed to dissolve 0.5 g of copper(II) carbonate?
Trả lời
(D)
8.09 ml
4
A plant virus is found to consist of uniform cylindrical particles of 150 Å in diameter and 5000 Å long. The specific volume of the virus is 0.75 cm3/g. If the virus is considered to be a single particle, find its molar mass.
Trả lời
(C)
7.09 × 10^7 g/mol
5
The electrons, identified by quantum numbers n and l, (i) n = 4, l = 1, (ii) n = 4, l = 0, (iii) n = 3, l = 2 and (iv) n = 3, l = 1 can be placed in order of increasing energy, from the lowest to highest, as
Trả lời
(A)
(iv)<(ii)<(iii)<(i)
6
Ground state electronic configuration of nitrogen atom can be represented by
Trả lời
A
D
7
Ionic radii of
Trả lời
(D)
P3+ > P5+
8
The correct order of increasing C - O bond length of CO, $$CO_3^{2-}$$, CO2 is
Trả lời
(D)
CO < CO2 < $$CO_3^{2-}$$
9
The geometry of H2S and its dipole moment are
Trả lời
(A)
angular and non-zero
10
One mole of nitrogen gas at 0.8 atm takes 38 s to diffuse through a pinhole. whereas one mole of an unknown compound of xenon with flourine at 1.6 atm takes 57 s to diffuse through the same hole. Calculate the molecular formula of the compound.
Trả lời
(D)
XeF₆
11
When 3.06 g of solid NH4HS is introduced into a two litre evacuated flask at 27o C, 30% of the solid decomposes into gaseous ammonia and hydrogen sulphide. (i) Kc and Kp for the reaction at 27o C (ii) What would happen to the equilibrium when more solid NH4HS is introduced into the flask?
Trả lời
(B)
Kc = 8.1 x 10^-5 mol^2 l^-2, Kp = 4.78 x 10^-2 atm^2, No change in equilibrium
12
Give reasons of the following:
BeCl2 can be easily hydrolysed.
Trả lời
(B)
The small size and high polarizing power of Be2+ distorts the water molecule, weakening the O-H bond and facilitating hydrolysis.
13
Nitrobenzene is formed as the major product along with a minor product in the reaction of benzene with a hot mixture of nitric acid and sulphuric acid. The minor product consists of carbon : 42.86 %, hydrogen : 2.40%, nitrogen : 16.67% and oxygen : 38.07% (i) Calculate the empirical formula of the minor product. (ii) When 5.5 g of the minor product is dissolved in 45 g of benzene, the boiling point of the solution is 1.84 oC higher than that of pure benzene. Calculate the molar mass of the minor product and determine its molecular and structural formula. (Molal boiling point elevation constant of benzene is 2.53 K kg mol-1)
Trả lời
(E)
168 g, C6H4(NO2)2, m-dinitrobenzene
14
A cell, Ag | Ag+ || Cu2+ | Cu, initially contains 1 M Ag+ and 1 M Cu2+ ions. Calculate the change in the cell potential after the passage of 9.65 A current for 1 h.
Trả lời
(B)
-0.010 V
15
The rate constant for an isomerisation reaction, A $$\to$$ B is 4.5 $$\times$$ 10-3 min-1. If the initial concentration of A is 1 M, calculate the rate of the reaction after 1 h.
