Product $(A)$ is

What will be the volume of $CO_2$ at $NTP$ obtained on heating $10 \ g$ of ($90\%$ pure) limestone (in $L$)?

What is the chemical name of Vitamin $B_1$?

If the direction cosines of two lines are given by $l+m+n=0$ and $l^2-5m^2+n^2=0$,then the angle between them is

Assign $A, B, C, D$ from the given type of reaction.
$P_4 + 6Cl_2 \xrightarrow{\Delta} 4PCl_3$

$A$ block of mass $M$ is pulled along a horizontal frictionless surface by a rope of mass $m$. If a force $P$ is applied at the free end of the rope,the force exerted by the rope on the block is-