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State and explain van't Hoff-Avogadro's law. |
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Answer» Solution :Statement of van't Hoff-Avogadro's law : At given temperature, equal volumes of the solutions having the same osmotic pressure contain equal number of solute particles. EXPLANATION: One mole of a substance contains Avogadro's number of MOLECULES (i.e., `6.02 xx 10^(23)` molecules). Therefore, the equal number of moles of the SUBSTANCES will contain equal number of molecules. The osmotic pressure, `pi` , is given by `pi` = CRT where C is the concentration of a solution in mol`dm^(-3)`. `pi - (n)/(v) RT` `therefore piprop (n)/(V)` at constant temperature. If two solutions contain `n_(A)` and `n_(B)` moles of two solutes in the equal volumes (V) of the solutions A and Bat the same temperature, then `pi_(A) prop n_(A//V)` and `pi_(B) prop n_(B//V)` `therefore (pi_(B))/(pi_(A)) =(n_(A))/(n_(B))` If `pi_(A) = pi_(B)` , then `n_(A) = n_(B)` |
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