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 : \(A_2 \rightleftharpoons 2A\)
A black body is at a temperature of 2880 K. The energy of radiation emitted by this body with wavelength between 499 nm and 500 nm is U1, between 999 nm and 1000 nm is U2 and between 1499 nm and 1500 nm is U3. The Wien's constant, b = 2.88×106 nm-K. Then,