The ratio of the number of water molecules in Mohr's salt and potash alum is $.... \times 10^{-1}$.

Match the following columns:

Column - $A$	Column - $B$
$(A)$ $88 \ g$ of $CO_2$	$(1)$ $0.2 \ mol$
$(B)$ $6.022 \times 10^{23}$ molecules of water	$(2)$ $2 \ mol$
$(C)$ $5.6 \ L$ of $O_2$ at $STP$	$(3)$ $1 \ mol$
$(D)$ $96 \ g$ of $O_2$	$(4)$ $6.022 \times 10^{23}$ molecules
$(E)$ One mole of any gas at $STP$	$(5)$ $3 \ mol$

The incorrect postulates of the Dalton's atomic theory are :
$A$. Atoms of different elements differ in mass.
$B$. Matter consists of divisible atoms.
$C$. Compounds are formed when atoms of different element combine in a fixed ratio.
$D$. All the atoms of given element have different properties including mass.
$E$. Chemical reactions involve reorganisation of atoms.
Choose the correct answer from the options given below :

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.

Iron sulphide is heated in air to form $A$,an oxide of sulphur. $A$ is dissolved in water to give an acid. The basicity of this acid is

Which of the following aqueous solutions is neutral?