NEET Chemistry Solved Question Paper 2003

Normality of the resulting mixture

$$\begin{gathered} = \frac{{\mathrm{N}}_1{\mathrm{V}}_1 + {\mathrm{N}}_2{\mathrm{V}}_2\hspace{0.17em}+ {\mathrm{N}}_3{\mathrm{V}}_3}{{\mathrm{V}}_1 + {\mathrm{V}}_2 + {\mathrm{V}}_3} \\ = \frac{75 \times {\displaystyle \frac{1}{5}} + 10 \times {\displaystyle \frac{1}{2}} + 30 \times {\displaystyle \frac{1}{10}}}{75 + 10 + 30} \\ = \frac{15\hspace{0.17em}+ 5 + 3}{115} \\ = \frac{23}{115} = \frac{\mathrm{N}}{5} = 0.2 \mathrm{N} \end{gathered}$$

0.2 N is the strength of the resulting acid mixture.

Among all the options given, Magnesium has the highest ionization energy. It is because magnesium has one more proton in its nucleus to hold on to the electrons in the 3s orbital.

Actual vapour density of methane

= $\frac{\mathrm{molecular} \mathrm{weight}}{2}$ = $\frac{16}{2}$ = 8

$\therefore$ Vapour density of volatile substance = 8 $\times$ 4 = 32

Molecular weight of the substance = 32 $\times$ 2 = 64

Heat of a reaction at constant pressure is equal to H_P - H_R.

In an isochoric process, $∆$V = 0, hence, work done P$∆$V = W = 0. So, $∆$E = q + 0. Hence, the increase in internal energy will be equal to heat absorbed by the system.

According to E = mc²

m = 1gm

c= 3$\times$10¹⁰ cm sec^-1

$\therefore$ E = 1gm $\times$ (3 $\times$ 10¹⁰ cm sec^-1)²

       = 9 $\times$ 10²⁰ ergs

1 gm of mass is equal to 9 x 10²⁰ ergs. Ergs or ergon (a Greek word) is the amount of work done by a force of one dyne exerted for a distance of one centimeter.

[H⁺] in a solution of weak acid of conc. C and dissociation constant K_c is given as

$$\begin{gathered} \left[{\mathrm{H}}^{+}\right] = \sqrt{{\mathrm{K}}_{\mathrm{a}} \times \mathrm{C} } = \sqrt{4.0 \times {10}^{-10} \times 2.5 \times {10}^{-1}} \\ = \sqrt{1 \times {10}^{-10}} \\ = 1 \times {10}^{-5} \mathrm{M} \\ \mathrm{pH} = -\log \left[{\mathrm{H}}^{+}\right] \\ = -\log {10}^{-5} = 5 \end{gathered}$$

Paramagnetic compounds have unpaired electrons. These are attracted to magnetic fields. 

Among all the given options, Cu⁺⁺ and Ni⁺⁺ are paramagnetic.

All the carbon atoms in benzene are in sp² state of hybridization, hence, all the six carbons and six hydrogen atoms attached with these carbon lie in a plane.

Human blood pH is 7.4. Therefore, option c is correct.