TS EAMCET 9-Sep-2020 Shift 2 Solved Paper

∵‌NaCl is an ionic salt and go for complete ionisation, so has maximum osmotic pressure, while glucose and urea does not ionises. For NaCl(i=2) and for glucose and urea (i=1)
∵‌‌π=iCRT
where,
π= osmotic pressure
i= van't Hoff factor
C= molarity
R= gas constant
T= temperature in Kelvin
Also, ‌‌π=i‌

n

V

RT‌‌[∵C=‌

n

V

]
and ‌‌π=i‌

w

M×V

RT
If V,R and T are same π∝i×‌

w

M

where, n= number of moles of solute
w= mass of solute
M= molar mass of solute
V= volume
Thus, (i) 30gmL−1 of glucose
(w=30,M=180)
π∝‌

1×30

180

=0.166
(ii) 60gmL−1 of NH2CONH2
(w=60,M=60)
π∝‌

1×60

60

=1.00
(iii) 80gmL−1 of glucose
(w=80,M=180)
π∝‌

1×80

80

=0.44
(iv) 58.5gmL−1 of NaCl
(i=2)w=58.5,M=58.5
∴‌‌π∝i‌

w

M

=2×‌

58.5

58.5

=2
Hence, order of osmotic pressure will be
(i) <(iii)<(ii)<(iv)