1
COMEDK 2025 Afternoon Shift
MCQ (Single Correct Answer)
+1
-0
The time needed for completion of $80 \%$ is $y$ times the half-life period of a first order reaction. What is the value of $y$ ?
A
0.648
B
3.46
C
2.32
D
0.322
2
COMEDK 2025 Afternoon Shift
MCQ (Single Correct Answer)
+1
-0
A current of 1.5 A is passed for 2 hours through an aqueous solution of $\mathrm{PdX} \mathrm{n}_{\mathrm{n}}$ where X is a monovalent anion. During the electrolysis process 2.977 g of Palladium metal gets deposited at the cathode. Calculate the charge on Pd ions. (Atomic mass of $\mathrm{Pd}=106.4 \mathrm{~g} / \mathrm{mol}$ ).
A
$\mathrm{n}=4$
B
$\mathrm{n}=6$
C
$\mathrm{n}=3$
D
$\mathrm{n}=2$
3
COMEDK 2025 Afternoon Shift
MCQ (Single Correct Answer)
+1
-0

Choose the statements which are incorrect in the case of Lanthanoids.

A. $\mathrm{Ce}^{4+}$ is diamagnetic while $\mathrm{Sm}^{3+}$ is paramagnetic.

B. The atomic size of the transition metals having atomic number greater than 71 are very close to that of the elements above them.

C. Lanthanoids react with hot water forming water soluble $\mathrm{Ln}(\mathrm{OH})_3$ with the liberation of $\mathrm{O}_2$.

D. The general electronic configuration of Lanthanoids is $(n-2) \mathrm{f}^{1-14} 5 \mathrm{~d}^0 6 \mathrm{~s}^2$, where $n=6$.

A
C & D
B
B & D
C
A & B
D
A & D
4
COMEDK 2025 Afternoon Shift
MCQ (Single Correct Answer)
+1
-0
Larger number of oxidation states are exhibited by the actinoids than those of lanthanoids. The reason is:
A
Lesser energy difference between 5 f and 6 d than between 4 f and 5 d orbitals
B
More energy difference between 5 f and 6 d than between 4 f and 5 d orbitals
C
4 f orbitals are more diffused than 5 f orbitals
D
Highly reactive nature of the actinoids
EXAM MAP
Medical
NEETAIIMS
Graduate Aptitude Test in Engineering
GATE CSEGATE ECEGATE EEGATE MEGATE CEGATE PIGATE IN
Civil Services
UPSC Civil Service
Defence
NDA
Staff Selection Commission
SSC CGL Tier I
CBSE
Class 12