<p>What volume at NTP of ammonia gas will be required to be passed into 30 mL of&nbsp;<math xmlns="http://www.w3.org/1998/Math/MathML"><mi>N</mi><msub><mi>H</mi><mn>2</mn></msub><mi>S</mi><msub><mi>O</mi><mn>4</mn></msub></math>&nbsp;to bring down the acid normality to 0.2 N?</p>