S$_\text{N}2$ reactions are stereospecific and proceed via a backside attack, resulting in the inversion of configuration at the chiral center.
S$_\text{N}1$ reactions occur via a carbocation intermediate, which is planar. As a result, nucleophiles can attack from either side, leading to a racemic mixture of products.
Thus:
\[ \text{S$_\text{N}2$} \rightarrow \text{Inversion (stereospecific)}, \quad \text{S$_\text{N}1$} \rightarrow \text{Racemization}. \]
Both statements are correct.
Consider the gas phase reaction: \[ CO + \frac{1}{2} O_2 \rightleftharpoons CO_2 \] At equilibrium for a particular temperature, the partial pressures of \( CO \), \( O_2 \), and \( CO_2 \) are found to be \( 10^{-6} \, {atm} \), \( 10^{-6} \, {atm} \), and \( 16 \, {atm} \), respectively. The equilibrium constant for the reaction is ......... \( \times 10^{10} \) (rounded off to one decimal place).
Molten steel at 1900 K having dissolved hydrogen needs to be vacuum degassed. The equilibrium partial pressure of hydrogen to be maintained to achieve 1 ppm (mass basis) of dissolved hydrogen is ......... Torr (rounded off to two decimal places). Given: For the hydrogen dissolution reaction in molten steel \( \left( \frac{1}{2} {H}_2(g) = [{H}] \right) \), the equilibrium constant (expressed in terms of ppm of dissolved H) is: \[ \log_{10} K_{eq} = \frac{1900}{T} + 2.4 \] 1 atm = 760 Torr.