Which of the following methods of expressing concentration are unitless?

Select the INCORRECT statement/s from the following:

(a) 22 books have infinite significant figures

(b) In the answer of calculation $2.5 \times 1.25$ has four significant figures,.

(c) Zero's preceding to first non-zero digit are significant

(d) In the answer of calculation $12.11+18.0+1.012$ has three significant figures

0.48 g of an organic compound on complete combustion produced 0.22 g of $\mathrm{CO}_2$. The percentage of C in the given organic compound is

An aqueous solution of alcohol contains $$18 \mathrm{~g}$$ of water and $$414 \mathrm{~g}$$ of ethyl alcohol. The mole fraction of water is

A pure compound contains $$2.4 \mathrm{~g}$$ of $$\mathrm{C}, 1.2 \times 10^{23}$$ atoms of $$\mathrm{H}, 0.2$$ moles of oxygen atoms. Its empirical formula is

$$0.4 \mathrm{~g}$$ of dihydrogen is made to react with $$7.4 \mathrm{~g}$$ of dichlorine to form hydrogen chloride. The volume of hydrogen chloride formed at $$273 \mathrm{~K}$$ and $$1 \mathrm{~bar}$$ pressure is

A gas mixture contains $$25 \% \mathrm{~He}$$ and $$75 \% \mathrm{~CH}_4$$ by volume at a given temperature and pressure. The percentage by mass of methane in the mixture is approximately _________.

A metal exists as an oxide with formula $$M_{0.96}$$ O. Metal, $$M$$ can exist as $$M^{2+}$$ and $$M^{3+}$$ in its oxide $$M_{0.96} \mathrm{O}$$. The percentage of $$\mathrm{M}^{3+}$$ in the oxide is nearly

The mass of $$\mathrm{AgCl}$$ precipitated when a solution containing $$11.70 \mathrm{~g}$$ of $$\mathrm{NaCl}$$ is added to a solution containing $$3.4 \mathrm{~g}$$ of $$\mathrm{AgNO}_3$$ is [Atomic mass of $$\mathrm{Ag}=108$$, Atomic mass of $$\mathrm{Na}=23$$]