When iron sulfide is heated in air,a sulfur oxide $A$ is obtained. When $A$ is dissolved in water,it produces an acid. What is the basicity of this acid?

Which of the following has the maximum mass?

Match the scientist's name in List-$A$ with their statement in List-$B$.

List-$A$	List-$B$
$(1)$ Roald Hoffmann	$(A)$ The proportion of the mass of elements in any compound is fixed.
$(2)$ Lavoisier	$(B)$ The smallest indivisible particle of matter is the atom.
$(3)$ Joseph Proust	$(C)$ Chemistry is not the science of $100$ elements.
$(4)$ Dalton	$(D)$ Matter can neither be created nor destroyed.

The correct order of the total number of atoms present in
$(A)$ $2$ moles of cyclohexane
$(B)$ $684 \text{ g}$ of sucrose
$(C)$ $90.8 \text{ L}$ of dihydrogen at $STP$
is:

Which of the following has the highest mass?

$10 \ mL$ of $2 \ M$ $NaOH$ solution is added to $20 \ mL$ of $1 \ M$ $HCl$ solution kept in a beaker. Now,$10 \ mL$ of this mixture is poured into a volumetric flask of $100 \ mL$ containing $2 \ moles$ of $HCl$ and made the volume up to the mark with distilled water. The solution in this flask is $:$