Which of the following rules states that it is impossible to determine simultaneously the exact position and exact momentum of an electron?

Calculate the cryoscopic constant of solvent when 2.5 gram solute is dissolved in 35 gram solvent lowers its freezing point by 3 K. (molar mass of solute is $117 \mathrm{~g} \mathrm{~mol}^{-1}$)

Which of the following solvents reduces the environmental pollution?

What is the number of electrons present in d-subshell if its atomic number is 27 and oxidation state is +2 ?