An isobar of ₂₀C⁴⁰ is

• ₁₈Ar⁴⁰

• ₂₀Ca³⁸

• ₂₀Ca⁴²

• ₁₈Ar³⁸

2.

In successive emission of $\mathrm{\alpha }$-and $\mathrm{\beta }$-particles, the number of $\mathrm{\alpha }$-and $\mathrm{\beta }$-particles should be emitted for the conversion of ₉₂U²³⁸ to ₈₂P²⁰⁶ are

• $7\mathrm{\alpha }, 5\mathrm{\beta }$

• $6\mathrm{\alpha }, 4\mathrm{\beta }$

• $4\mathrm{\alpha }, 3\mathrm{\beta }$

• $8\mathrm{\alpha }, 6\mathrm{\beta }$

Cell reaction is spontaneous, when

• ${\mathrm{E}}_{\mathrm{red}}^{°} \mathrm{is} \mathrm{negative}$

• ${\mathrm{E}}_{\mathrm{red}}^{°} \mathrm{is} \mathrm{positive}$

• $∆\mathrm{G}° \mathrm{is} \mathrm{negative}$

• $∆\mathrm{G}° \mathrm{is} \mathrm{positive}$

If $∆\mathrm{E}$  is the heat of reaction for

${\mathrm{C}}_2{\mathrm{H}}_5\mathrm{OH}\left(\mathrm{l}\right) + 3{\mathrm{O}}_2\left(\mathrm{g}\right) \to 2{\mathrm{CO}}_2\left(\mathrm{g}\right) + 3{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right) \mathrm{at} \mathrm{constant} \mathrm{volume}, \mathrm{the} ∆\mathrm{H}$ (heat of reaction at constant pressure), at constant temperature is

• $∆\mathrm{H} = ∆\mathrm{E} + \mathrm{RT}$

• $∆\mathrm{H} = ∆\mathrm{E} - \mathrm{RT}$

• $∆\mathrm{H} = ∆\mathrm{E} - 2\mathrm{RT}$

• $∆\mathrm{H} = ∆\mathrm{E} + 2\mathrm{RT}$

Which one of the following species acts as both Bronsted acid and base?

• ${\mathrm{H}}_2{\mathrm{PO}}_2^{-}$

• ${\mathrm{HPO}}_3^{2-}$

• ${\mathrm{HPO}}_4^{2-}$

• All of these

$$\begin{gathered} \mathrm{If} \mathrm{C}\left(\mathrm{s}\right) + {\mathrm{O}}_2\left(\mathrm{g}\right) \to \mathrm{CO}\left(\mathrm{g}\right); ∆\mathrm{H} = \mathrm{r} \\ \mathrm{and} \mathrm{CO}\left(\mathrm{g}\right) + \frac{1}{2}{\mathrm{O}}_2\left(\mathrm{g}\right) \to {\mathrm{CO}}_2\left(\mathrm{g}\right); ∆\mathrm{H} =\mathrm{s} \mathrm{then}, \mathrm{the} \mathrm{heat} \mathrm{of} \mathrm{formation} \mathrm{of} \mathrm{CO} \mathrm{is} \end{gathered}$$

• r+s

• r-s

• s-r

• rs

Which of the following concentration factors is affected by change in temperature?

• Molarity

• Molality

• Mole fraction

• Weight fraction

Which of the following has the maximum penetrating power ?

• $\mathrm{\alpha }-$ particle

• $\mathrm{\gamma }-$particles

• Proton

• Positron

Solubility of Ca(OH)₂ is s mol L^-1. The solubility product (K_sp) under the same condition is

• 4s³

• 3s⁴

• 4s²

• s³

The pH of a 0.1 M solution of NH₄OH (having K_b =1.0 x 10^-5) is equal to

• 10

• 6

• 11

• 12