Let's analyze each statement given in the question to determine which are correct:
Based on the analysis, the correct statements are A and C. Thus, the option "A and C only" is the correct answer.
Let’s analyze each statement individually:
Statement A: \( \text{Mn}_2\text{O}_7 \) is an oil at room temperature. - \( \text{Mn}_2\text{O}_7 \) (manganese heptoxide) is indeed a dark green oil that is highly unstable and explosive at room temperature. It is a covalent oxide and behaves as an acidic oxide due to its high oxidation state. Therefore, this statement is correct.
Statement B: \( \text{V}_2\text{O}_4 \) reacts with acid to give \( \text{VO}_2^{2+} \). - \( \text{V}_2\text{O}_4 \) (vanadium(IV) oxide) is an amphoteric oxide. It can react with acids, undergoing oxidation, to form the \( \text{VO}_2^{2+} \) ion (vanadyl ion). This reaction occurs as:
\[ \text{V}_2\text{O}_4 + 2\text{H}^+ \to 2\text{VO}_2^{2+} + \text{H}_2\text{O} \]
Therefore, this statement is also correct.
Statement C: \( \text{CrO} \) is a basic oxide. - \( \text{CrO} \) (chromium(II) oxide) is a basic oxide. It reacts readily with acids to form salts and water. For example:
\[ \text{CrO} + 2\text{HCl} \to \text{CrCl}_2 + \text{H}_2\text{O} \]
This confirms that \( \text{CrO} \) behaves as a basic oxide, so this statement is correct.
Statement D: \( \text{V}_2\text{O}_5 \) does not react with acid. - \( \text{V}_2\text{O}_5 \) (vanadium(V) oxide) is an amphoteric oxide, meaning it can react with both acids and bases. In fact, \( \text{V}_2\text{O}_5 \) can react with acidic solutions, such as hydrochloric acid, and undergo reduction. Therefore, this statement is incorrect.
Since statements A and C are correct, the correct answer is Option (2).
What will be the equilibrium constant of the given reaction carried out in a \(5 \,L\) vessel and having equilibrium amounts of \(A_2\) and \(A\) as \(0.5\) mole and \(2 \times 10^{-6}\) mole respectively?
The reaction : \(A_2 \rightleftharpoons 2A\)

Cobalt chloride when dissolved in water forms pink colored complex $X$ which has octahedral geometry. This solution on treating with cone $HCl$ forms deep blue complex, $\underline{Y}$ which has a $\underline{Z}$ geometry $X, Y$ and $Z$, respectively, are
Cobalt chloride when dissolved in water forms pink colored complex $X$ which has octahedral geometry. This solution on treating with cone $HCl$ forms deep blue complex, $\underline{Y}$ which has a $\underline{Z}$ geometry $X, Y$ and $Z$, respectively, are
| (a) \([Cr(H_2O)_6]^{+3}\) | (i) \(t^2_{2g}eg^0\) |
| (b) \([Fe(H_2O)_6]^{+3}\) | (ii) \(t^3_{2g}eg^0\) |
| \((c) [Ni(H_2O)_6]^{+2}\) | (iii) \(t^3_{2g}eg^2\) |
| (d) \([V(H_2O)_6]^{+3}\) | (iv) \(t^6_{2g}eg^2\) |
What will be the equilibrium constant of the given reaction carried out in a \(5 \,L\) vessel and having equilibrium amounts of \(A_2\) and \(A\) as \(0.5\) mole and \(2 \times 10^{-6}\) mole respectively?
The reaction : \(A_2 \rightleftharpoons 2A\)