1.2% (mass/volume) solution of NaCl is isotonic with 7.2% (mass/volume) solution of glucose. The degree of ionization of NaCl is (molar mass of NaCl=58.5 molar mass of glucose = 180)

1.2 g of NaCl is 100 ml of solution $\Rightarrow$ 1 litre $=12g=\frac{12}{58.5}M$

7.2 g of glucose is 100 ml of solution $\Rightarrow$1 litre $=72g=\frac{72}{180}$

$NaCl$               Glucose

$i_1=1+\alpha i_2=1$

$C_1=\left(\frac{12}{58.5}\right)C_2=\frac{72}{180}{i}_1{C}_1=i_2{C}_2$

$(1+\alpha )\left(\frac{12}{58.5}\right)=\frac{72}{180}$

 $\alpha =\frac{58.5}{30}-1=0.95$