<p>A solution of sodium sulphate contains 92g of&nbsp;<math xmlns="http://www.w3.org/1998/Math/MathML"><mi>N</mi><msup><mi>a</mi><mo>+</mo></msup></math>&nbsp;ions per kg of water. The molality of&nbsp;<math xmlns="http://www.w3.org/1998/Math/MathML"><mi>N</mi><msup><mi>a</mi><mo>+</mo></msup></math>&nbsp;ions per kg of water. The molality of&nbsp;<math xmlns="http://www.w3.org/1998/Math/MathML"><mi>N</mi><msup><mi>a</mi><mo>+</mo></msup></math>&nbsp;ions is</p>