$K_2CS_3$ is called potassium ...... .

Which of the following compounds does not have similarity in their structural aspect?

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.

State whether the following statements are true or false:
$(i)$ The molarity of a $0.6 \ N$ aqueous solution of ${H_3PO_3}$ is $1.2 \ M$.
$(ii)$ $\text{Empirical formula} = n \times \text{Molecular formula}$.
$(iii)$ In ${Cl_2O}$,the weight of chlorine combining with $8 \ g$ of oxygen is $35.5 \ g$.

If one liter of air is repeatedly passed over heated copper and magnesium until no further reduction in volume occurs,the final volume of the air will be approximately ......... $mL$.

If $10^{23}$ molecules are removed from $5.6 \ L$ of an ideal gas at $273 \ K$ and $2 \ atm$ pressure,how many moles of the gas will remain?