a
\(\Delta {{\text{T}}_{{\text{f(KCl)}}}}{\text{  =  }}{{\text{i}}_{{\text{KCl}}}}{\text{ }} \times {{\text{K}}_{\text{f}}}{\text{ }} \times {\text{ }}{{\text{m}}_{{\text{KCl}}}}\)

\(\Delta {K_{f(BaC{l_2})}} = {i_{BaC{l_2}}} \times {K_f} \times {m_{BaC{l_2}}}\)

\(\therefore {K_f} = \frac{{\Delta {T_{f(KCl)}}}}{{{i_{KCl}} \times {m_{KCl}}}} = \frac{{\Delta {T_{f(BaC{l_2})}}}}{{{i_{(BaC{l_2})}} \times {m_{BaC{l_2}}}}}\)

\(\therefore {K_f} = \frac{2}{{2 \times 0.01}} = \frac{{\Delta {T_{f(BaC{l_2})}}}}{{3 \times 0.01}}\)

\(\therefore {\text{ }}\Delta {{\text{T}}_{{\text{f(BaC}}{{\text{l}}_{\text{2}}}{\text{)}}}}{\text{  =  3}}{{\text{ }}^ \circ }\) સે 

\(\therefore {\text{ BaC}}{{\text{l}}_{\text{2}}}\) નું ઠારબિદુ \({\text{  =  0  -  }}\Delta {{\text{T}}_{\text{f}}}\,\,\,{\text{ =  0  -  3  =   - 3}}{{\text{ }}^ \circ }\) સે