Question 9
For acid-base equilibrium, the reaction always favours theformation of the
a) Strongest acid and the Strongest base
b) Weakest acid and the strongest base
c) Weakest acid and the weakest base
d) Strongest acid and the weakest base
e) Either a or c
Correct Answer:
c) Weakest acid and weakest base
Explanation:
In an acid-base equilibrium, the reaction always favours the formation of the weakest acid and the
weakest base due to their stability. The weakest acid and the weakest base must always be on the
same side of the reaction.
Question 10
The oxidation state of oxygen in OF
2
is
a) -2
b) +1
c) -1
d) +2
e) 0
Correct Answer:
d) +2
Explanation:
It's an unusual compound, in which oxygen takes the positive oxidation number +2. Because F is
more electronegative than O, therefore F gets the -1 oxidation state and O gets the positive oxidation
state.
Question 11
Calculate the angle at which second order reflection will occur in an X-ray spectrometer when
X-
rays of wavelength 1.54λ are diffracted by atoms of a crystal, with interplanar distance of
4.04 A
0
.
a) 10
0
59'
b) 22
0
24'
c) 24
0
22'
d) 59
0
10'
e) 12
0
50'
Correct Answer:
b) 22
0
24'
Explanation:
Given data: λ = 1.55, d = 4.04 A
0
For second order reflection n=2,
Bragg equation is 2d sin Θ = 2λ
Θ = sin
-1
(λ/d) = sin
-1
(0.381) = 22
0
24'
