Mark the species among the following that contains the highest number of atoms.

1. 4 g He

2. 46 g Na

3. 0.40 g Ca

4. 12 g He

If the concentration of glucose  (C₆H₁₂O₆)  in the blood is 0.9 g L^-1, then the molarity of glucose in the blood is 
1. 5 M
2. 50 M
3. 0.005 M
4. 0.05 M

The molality of a solution containing 18.25 g of HCl gas in 500 g of water is -

The number of molecules of H₂SO₄ present in 100 mL of 0.02 M H₂SO₄ solution is: 

1. $12.044\times {10}^{20}$ molecules

2. $6.022\times {10}^{23}$ molecules

3. $1\times {10}^{23}$ molecules

4. $12.044\times {10}^{23}$ molecules

The mass percent of carbon in carbon dioxide is : 

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 -

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 incorrect statement among the following is:

Which of the following statements is correct about the reaction is given below?

$4\mathrm{Fe}\left(\mathrm{s}\right)+3{\mathrm{O}}_2\left(\mathrm{g}\right)\to 2{\mathrm{Fe}}_2{\mathrm{O}}_3\left(\mathrm{g}\right)$

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