NEET Chemistry MCQs

A mixture of $CaCO_3$ and $MgCO_3$ weighing 1.84 g on heating leaves a residue weighing 0.96 g. If the percentage by mass of $CaCO_3$ in the original mixture is x%, what is the value of x/2?

A 20 L vessel contains 0.1 mole of $O_2$ at 300 K. $O_3$ is prepared in the vessel by subjecting $O_2$ to silent electric discharge till the volume is reduced to 15 L at 300K. What is the number of moles of $O_3$ formed?

Equal masses of oxygen and ozone are present in a container at 298 K. The ratio of their partial pressures ($P_{O_2} : P_{O_3}$) is:

A compound contains 28% nitrogen and 72% of a metal by weight. Three atoms of metal combine with two atoms of nitrogen. If the atomic weight of nitrogen is 14, the atomic weight of the metal is:

A solution is prepared by dissolving 2.5g of a non-volatile solute in 100g of water. The vapor pressure of the solution is found to be 22.87 Torr at $25^\circ C$. If the vapor pressure of pure water is 23.76 Torr at the same temperature, what is the molar mass of the solute (in g/mol)?

Which of the following methods is NOT suitable for concentrating a protein solution?

A colloidal solution of gold nanoparticles is prepared by reduction of $HAuCl_4$. Which of the following methods is MOST EFFECTIVE for purifying this solution from excess reactants and small ionic byproducts?

A metal M forms a volatile carbonyl complex $M(CO)_x$. 0.525g of this complex is heated in a closed vessel of volume 250 mL at $50^\circ C$. The pressure inside the vessel after complete decomposition of the complex is 746 Torr. If the gas constant R is 0.0821 L atm $K^{-1} mol^{-1}$, what is the value of x in the formula $M(CO)_x$? (Assume the metal M does not contribute significantly to the pressure)

Two vectors $\vec{A}$ and $\vec{B}$ have equal magnitudes. Under what condition will their difference have the same magnitude as either of the vectors?

A unit vector perpendicular to both $\hat{i} + \hat{j}$ and $\hat{j} + \hat{k}$ is: