Question

18 G of glucose is dissolved in 180 gram of water, the relative lowering in vapour pressure is
1) 0.001
2) 10
3) 1.8
4) 0.01
kindly give answer with solution. ​

Answer 1

Answer:

Vapor Pressure lowering is governed by Raoult's law, which basically states:

P

n

=

(

X

n

)

×

P

o

were

P

n

is the new vapor pressure,

X

n

is the mole faction of the solvent, and

P

o

is the pure solvent vapor pressure.

I think the relative lowering would be

(

1

−

P

n

P

o

)

, which is

(

1

−

X

n

)

X

n

=

moles of water

total moles

X

n

=

10

10.1

=

0.99009901

Relative Lowering:

(

1

−

0.99009901

)

=

0.00990099

=

0.01

Explanation:

So 0.01 is your answer

Answer 2

Vapour pressure lowering is governed by Raouilt law.

Pn=Xn × Po

Pn is the new vapour pressure

Xn is the moles

Po is the pure solvent vapour pressure

(1-Pn/Po)

(1-Xn)

Xn = moles of water / total moles

Xn = 10/10.1 = 0.99009901

( 1-Xn)

(1-0.99009901)

0.00990099 equal = 0.01