Match the following:

	Column-I		Column-II
A.	88 g of CO2	1.	0.25 mol
B.	6.022×1023 molecules of H2O	2.	2 mol
C.	5.6 L of O2 at STP	3.	3 mol
D.	96 g of O2	4.	1 mol

Codes:

	A	B	C	D
1.	2	4	1	3
2.	1	2	3	4
3.	1	4	3	2
4.	4	1	3	2

Match the following physical quantities with units.

Codes:

Identify the reaction that does not obey the law of conservation of mass from the provided options:

1. $2\mathrm{Mg}\left(\mathrm{s}\right)+{\mathrm{O}}_2\left(\mathrm{g}\right)\to 2\mathrm{MgO}\left(\mathrm{s}\right)$

2. ${\mathrm{C}}_3{\mathrm{H}}_8\left(\mathrm{g}\right)+{\mathrm{O}}_2\left(\mathrm{g}\right)\to {\mathrm{CO}}_2\left(\mathrm{g}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{g}\right)$

3. ${\mathrm{P}}_4\left(\mathrm{s}\right)+5{\mathrm{O}}_2\left(\mathrm{g}\right)\to {\mathrm{P}}_4{\mathrm{O}}_{10}\left(\mathrm{s}\right)$

4. ${\mathrm{CH}}_4\left(\mathrm{g}\right)+2{\mathrm{O}}_2\left(\mathrm{g}\right)\to {\mathrm{CO}}_2\left(\mathrm{g}\right)+2{\mathrm{H}}_2\mathrm{O}\left(\mathrm{g}\right)$

If the density of the solution is 3.12 g ml^-1, then what will be the mass of the 1.5 ml solution in two significant figures?

The empirical formula and molecular mass of a compound are ${\mathrm{CH}}_2\mathrm{O}$ and 180 g, respectively. The molecular formula of the compound is:
1. C₉H₁₈O₉
2. CH₂O
3. C₆H₁₂O₆
4. C₂H₄O₂

2. 46 g Na

3. 0.40 g Ca

4. 12 g He

1. 1.5 M

2. 1.66 M

3. 0.017 M

4. 1.59 M

Two students performed the same experiment separately, and each of them recorded two readings of mass, which are given below. The correct reading of mass is 3.0 g. On the basis of the given data, mark the correct option out of the following statements.

10 g of a silver coin, when dissolved completely in excess of conc. HNO₃ gives 8.5 g of silver nitrate.
The percentage purity of the coin is:
(Molar mass of silver is 108g)