The number of possible enantiomeric pairs that can be produced during mono-chlorination of $2$-methylbutane is

Two closed organ pipes of length $100\,cm$ and $101\,cm$ long give $16$ beats in $20\,sec$ when each pipe is sounded in fundamental mode. Calculate the velocity of sound in $m/s$.

$A$ hollow sphere and a solid sphere having the same mass and same radius are rolled down a rough inclined plane. Which of the following statements is correct?

What is the function of the spleen in humans?

Which of the following reagents is used to distinguish acetone and acetophenone?

An inverted bell lying at the bottom of a lake $47.6 \, m$ deep has $50 \, cm^3$ of air trapped in it. The bell is brought to the surface of the lake. The volume of the trapped air will be ......... $cm^3$ (atmospheric pressure $= 70 \, cm$ of $Hg$ and density of $Hg = 13.6 \, g/cm^3$).