If 500 mL of a 5 M solution is diluted to 1500 mL, the molarity of the resultant solution is: 

1. 1.5 M

2. 1.66 M

3. 0.017 M

4. 1.59 M

2. 46 g Na

3. 0.40 g Ca

4. 12 g He

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

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?

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

Match the following:

Match the following physical quantities with units.

Codes:

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)