If one wants to make methanol out of synthesis gas,what should be the ratio of the gaseous components in the synthesis gas?

The hardness of a water sample containing $10^{-3} \; M \; MgSO_{4}$ expressed as $CaCO_{3}$ equivalents (in $ppm$) is (molar mass of $MgSO_{4}$ is $120.37 \; g/mol$)

The weight of sodium carbonate required to prepare $500 \ mL$ of a semi-normal solution is .......... $g$.

When the same amount of zinc is treated separately with an excess of sulphuric acid and an excess of sodium hydroxide solution,the ratio of the volumes of hydrogen evolved is:

At $STP$,the volume of $4.4 \, g$ of an unknown gas is $2.24 \, L$. Which of the following is this gas?

What is the quantity of sugar charcoal remaining behind after charring $17.1 \ g$ of sugar using conc. $H_2SO_4$ under ideal conditions (in $g$)?