Question

can someone explain the answer plz!!!!

Answer 1

The given molecule C_12 H_22 O_11 is sucrose.

• Sucrose of not dissociable in water hence Vant Hoff factor is 1

i.e

• i=1
• molality=m=0.3
• k=freezing point constant (As we don't need to find the perfect freezing point let's keep it constant)

$\boxed{\sf T_f=kmi}$

• T_f is freezing point

For Sucrose

$\\ \sf\longmapsto T_f=1(0.3)k=0.3k$

Now.

Let's check Vant Hoff factor of each compound.

• AlCl_3=4
• CuCl_2=3
• NaCl=2
• C_6H_12O=1

Let's count Freezing point of each compound.

AlCl_3

• m=0.075

$\\ \sf\longmapsto T_f=0.075(4)k=0.3k$

Option A is correct

CuCl_2

• m=0.15

$\\ \sf\longmapsto T_f=0.15(3)k=0.75k$

NaCl:-

• m=0.3

$\\ \sf\longmapsto T_f=0.3(2)k=0.6k$

Glucose:-

• m=0.6

$\\ \sf\longmapsto T_f=0.6k$

Hence option A is correct