Determine the correct order of the property mentioned against them : (a) 10% glucose (p1 ), 10% urea (p2 - Chemistry - Solutions

Question

Determine the correct order of the property mentioned against them
: (a) 10% glucose (p1 ), 10% urea (p2 ), 10% sucrose (p3 ) [osmotic
pressure] (b) 0 1 m nacl, 0 1 m urea, 0 1 m mgcl2 [elevation in b
pt ] (c) 0 1 m cacl2 , 0 1 m sucrose, 0 1 m nacl [depression in
freezing point]

Vartika Jain · Accepted Answer

Dear Student,

All the properties are colligative properties
 (a) π= iMRTwhere, M is molarityand, M=massmolar mass×1volumeNow, osmotic pressure is directly proportional to molarity which is inversely related to molar massTherefore, π α 1Molar massMolar mass of glucose=180 gMolar mass of urea= 60 gMolar mass of sucrose=342 gSucrose has higher molar mass, so lowest osmotic pressure
 Therefore, order isp2 > p1 > p3(b) ∆Tb= KbmGreater the molality of the solution, greater will be the elevation in boiling point
 Here molality is same, but molar mass is diff
 and, molar mass α 1molalityTherefore, ∆Tbα 1molar massMolar mass of NaCl=58 gMolar mass of Urea=60 gMolar mass of MgCl2=95 gTherefore, order will be 0
1 m NaCl > 0 1 m urea >0
1 m MgCl2(c)∆Tf= KfmMolar mass of CaCl2=110 gMolar mass of NaCl=58 gMolar mass of sucrose=342 gSimilarly, the order will be 0
1 m NaCl > 0
1 m CaCl2 > 0 1 m sucrose

Determine the correct order of the property mentioned against them : (a) 10% glucose (p1 ), 10% urea (p2 ), 10% sucrose (p3 ) [osmotic pressure] (b) 0.1 m nacl, 0.1 m urea, 0.1 m mgcl2 [elevation in b.pt.] (c) 0.1 m cacl2 , 0.1 m sucrose, 0.1 m nacl [depression in freezing point]