Calculate molality of solution of a nonvolatile solute having boiling point elevation $$1.89 \mathrm{~K}$$ if boiling point elevation constant of solvent is $$3.15 \mathrm{~K} \mathrm{~kg} \mathrm{~mol}^{-1}$$.

What type of following phenomena does the Cannizzaro reaction exhibit?

If $$\overline{\mathrm{a}}, \overline{\mathrm{b}}, \overline{\mathrm{c}}$$ are three vectors, $$|\overline{\mathrm{a}}|=2,|\overline{\mathrm{b}}|=4,|\overline{\mathrm{c}}|=1, |\bar{b} \times \bar{c}|=\sqrt{15}$$ and $$\bar{b}=2 \bar{c}+\lambda \bar{a}$$, then the value of $$\lambda$$ is

The centroid of tetrahedron with vertices at $$\mathrm{A}(-1,2,3), \mathrm{B}(3,-2,1), \mathrm{C}(2,1,3)$$ and $$\mathrm{D}(-1,-2,4)$$ is