80 mole percent of $$\mathrm{MgCl}_{2}$$ is dissociated in aqueous solution. The vapour pressure of $$1.0 ~\mathrm{molal}$$ aqueous solution of $$\mathrm{MgCl}_{2}$$ at $$38^{\circ} \mathrm{C}$$ is ____________ $$\mathrm{mm} ~\mathrm{Hg.} ~\mathrm{(Nearest} ~\mathrm{integer)}$$
Given : Vapour pressure of water at $$38^{\circ} \mathrm{C}$$ is $$50 \mathrm{~mm} ~\mathrm{Hg}$$
Values of work function (W$$_0$$) for a few metals are given below
Metal | Li | Na | K | Mg | Cu | Ag |
---|---|---|---|---|---|---|
W$$_0$$/eV | 2.42 | 2.3 | 2.25 | 3.7 | 4.8 | 4.3 |
The number of metals which will show photoelectric effect when light of wavelength $$400 \mathrm{~nm}$$ falls on it is ___________
Given: $$\mathrm{h}=6.6 \times 10^{-34} \mathrm{~J} \mathrm{~s}$$
$$c=3 \times 10^{8} \mathrm{~ms}^{-1}$$
$$e=1.6 \times 10^{-19} \mathrm{C}$$
At $$600 \mathrm{~K}$$, the root mean square (rms) speed of gas $$\mathrm{X}$$ (molar mass $$=40$$ ) is equal to the most probable speed of gas $$\mathrm{Y}$$ at $$90 \mathrm{~K}$$. The molar mass of the gas $$\mathrm{Y}$$ is ___________ $$\mathrm{g} ~\mathrm{mol}^{-1}$$. (Nearest integer)
Three organic compounds A, B and $$\mathrm{C}$$ were allowed to run in thin layer chromatography using hexane and gave the following result (see figure). The $$\mathrm{R}_{\mathrm{f}}$$ value of the most polar compound is ____________ $$\times 10^{-2}$$