1
COMEDK 2023 Evening Shift
MCQ (Single Correct Answer)
+1
-0

A first order reaction proceeds to $$90 \%$$ completion. What will be the approximate time taken for $$90 \%$$ completion in relation to $$t_{1 / 2}$$ of the reaction?

A
5.02 times of $$\mathrm{t}_{1 / 2}$$
B
4.54 times of $$\mathrm{t}_{1 / 2}$$
C
5.66 times of $$\mathrm{t}_{1 / 2}$$
D
3.32 times of $$\mathrm{t}_{1 / 2}$$
2
COMEDK 2023 Evening Shift
MCQ (Single Correct Answer)
+1
-0

What would be the volume of water required to dissolve $$0.2 \mathrm{~g}$$ of $$\mathrm{PbCl}_2$$ of molar mass $$278 \mathrm{~g} / \mathrm{mol}$$ to prepare a saturated solution of the salt? $$(\mathrm{K}_{\mathrm{SP}}$$ of $$\mathrm{PbCl}_2=3.2 \times 10^{-8})$$

A
1000 ml
B
359.7 ml
C
278.8 ml
D
360.4 ml
3
COMEDK 2023 Evening Shift
MCQ (Single Correct Answer)
+1
-0

Which one of the following compounds would not undergo Aldol condensation?

A
Phenyl ethanal
B
1- Phenyl propanone.
C
2,2-Dimethyl butanal
D
2- Methyl pentanal
4
COMEDK 2023 Evening Shift
MCQ (Single Correct Answer)
+1
-0

Match the following characteristics of transition metals given in Column I with the examples listed in Column II

S. No. Characteristic properties S. No. Examples
W Chemically inert, non-stoichiometric compound A $$\mathrm{WO}_3$$
X Higher oxidation states are more stable B $$\mathrm{TiCl_4}$$
Y Due to inert pair effect, lower oxidation state is more stable C $$\mathrm{Mn_4N}$$
Z. Colourless compound of transition metal D $$\mathrm{SnCl_2}$$

A
$$ \mathrm{W}=\mathrm{B} \quad \mathrm{X}=\mathrm{C} \quad \mathrm{Y}=\mathrm{D} \quad \mathrm{Z}=\mathrm{A} $$
B
$$ \mathrm{W}=\mathrm{C} \quad \mathrm{X}=\mathrm{D} \quad \mathrm{Y}=\mathrm{A} \quad \mathrm{Z}=\mathrm{B} $$
C
$$ \mathrm{W}=\mathrm{C} \quad \mathrm{X}=\mathrm{A} \quad \mathrm{Y}=\mathrm{D} \quad \mathrm{Z}=\mathrm{B} $$
D
$$ \mathrm{W}=\mathrm{A} \quad \mathrm{X}=\mathrm{D} \quad \mathrm{Y}=\mathrm{C} \quad \mathrm{Z}=\mathrm{B} $$
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