<p>0.98g of a polybasic acid (mol. wt. 98) requires 30 mL of 0.5 M Ba<math xmlns="http://www.w3.org/1998/Math/MathML"><msub><mfenced><mrow><mi>O</mi><mi>H</mi></mrow></mfenced><mn>2</mn></msub></math>&nbsp;for complete neutralisation. The basicity of acid is.............</p>