Question

Which aqueous solution has the lowest vapor pressure?

0.2 molal calcium nitrate

0.2 molal magnesium sulfate

0.2 molal methanol

0.2 molal potassium phosphate

Answer 1

Answer:

calcium nitrate: Ca(NO3)2 will give us: Ca2+ + 2(NO3) 3 ions ---Answer

Magnesium sulfate (MgSO4) gives us Mg2+ + (SO4)2- gives 2 ions

methanol(CH3OH) gives two ions

potassium
phosphate(KH₂PO₄) also gives 2 ions

the greater the number of ions, greater is the colligative property. As lowering of vapor pressure is a colligative property calcium nitrate: Ca(NO3)2 will have the lowest vapor pressure.

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