54. A body of mass 5 kg is moving in a circle of radius 1 m with
an angular velocity of 2 radian/sec. The centripetal force is
(a) 10N (b) 20N
(C) 30 N
40N
Answers
Answered by
0
Correct option is
B
90 amu
Given data
Wt of A=20 gm
P
A
0
=10 torr
molecular mass of A=200 amu
Wt of B=1 gm
P
solution
=9 torr
molecular mass of B=?
This problem can be solved by using the relative lowering of vapour pressure.
P
0
P
0
−P
=
n
1
+n
2
n
2
P
0
= Vapour pressure of pure solvent
P= Vapour pressure of solution
n
2
= moles of solute
n
1
= moles of solvent
10
10−9
=
200
20
+
x
1
x
1
[
10
1
+
x
1
]
10
1
=
x
1
100
1
+
10x
1
=
x
1
100
1
=
x
1
−
10x
1
=
10x
9
∴ The molecular mass of compound (solute) B is 90 amu
10x=900
x=90amu
Hence, the correct option is B
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