1
COMEDK 2024 Afternoon Shift
MCQ (Single Correct Answer)
+1
-0

Consider the following statements in respect of lanthanides, which of the statements are incorrect?

(i) $$\mathrm{La}(\mathrm{OH})_3$$ is least basic among the hydroxides of lanthanides

(ii) The lanthanide ions $$\mathrm{Yb}^{2+}, \mathrm{Lu}^{3+}$$ and $$\mathrm{Ce}^{4+}$$ are diamagnetic in nature.

(iii) $$\mathrm{Ce}^{4+}$$ can act as an oxidising agent

(iv) $$\operatorname{Ln}$$ (III) compounds are generally colourless

(v) Ionic radii of $$\mathrm{Ce}^{3+}$$ is greater than $$\mathrm{Yb}^{3+}$$

A
(i), (ii) and (iii)
B
(i) and (iv)
C
(iii), (iv) and (v)
D
(iii) and (iv)
2
COMEDK 2024 Afternoon Shift
MCQ (Single Correct Answer)
+1
-0

Which of the following is not aromatic?

COMEDK 2024 Afternoon Shift Chemistry - General Organic Chemistry Question 2 English

A
D
B
C
C
A
D
B
3
COMEDK 2024 Afternoon Shift
MCQ (Single Correct Answer)
+1
-0

Among the following compounds, the most acidic is :

A
3, 4-dinitrobenzoic acid
B
Benzoic acid
C
4-methoxybenzoic acid
D
4-nitrobenzoic acid
4
COMEDK 2024 Afternoon Shift
MCQ (Single Correct Answer)
+1
-0

Given below a first order reaction in the gas phase

$$\mathrm{A}(\mathrm{g}) \rightarrow \mathrm{B}(\mathrm{g})+\mathrm{C}(\mathrm{g})$$

If the initial pressure of the system is $$\mathrm{P}_{\mathrm{i}}$$ and the total pressure at $$\mathrm{t}$$ seconds is $$\mathrm{P}_{\mathrm{t}}$$, the rate constant $$\mathrm{k}$$ for the reaction is:

A
$$ \mathrm{k}=\frac{2.303}{\mathrm{t}} \log \frac{\mathrm{P}_{\mathrm{i}}}{\mathrm{P}_{\mathrm{t}}} $$
B
$$ \mathrm{k}=\frac{2.303}{\mathrm{t}} \log \frac{\mathrm{P}_{\mathrm{i}}}{\left(2 \mathrm{P}_{\mathrm{i}}-\mathrm{P}_{\mathrm{t}}\right)} $$
C
$$ \mathrm{k}=\frac{2.303}{\mathrm{t}} \log \frac{\mathrm{P}_{\mathrm{i}}}{\left(2 \mathrm{P}_{\mathrm{i}}+\mathrm{x}\right)} $$
D
$$ \mathrm{k}=\frac{2.303}{\mathrm{t}} \log \frac{\mathrm{P}_{\mathrm{i}}}{\left(\mathrm{P}_{\mathrm{i}}+\mathrm{x}\right)} $$
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