1
WB JEE 2026
MCQ (Single Correct Answer)
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-0.25
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Which one of the following cations gives a chocolate brown precipitate upon addition of aqueous solution of $\mathrm{K}_4\left[\mathrm{Fe}(\mathrm{CN})_6\right]$ ?

A

$\mathrm{Fe}^{3+}$

B

$\mathrm{Cu}^{2+}$

C

$\mathrm{Zn}^{2+}$

D

$\mathrm{Ca}^{2+}$

2
WB JEE 2026
MCQ (Single Correct Answer)
+1
-0.25
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A compound contains two types of atoms $A$ and $B$ .Its crystal structure is a cubic lattice with'$A$' atoms at the corner of the unit cells and'$B$'atoms at the body centres.The simplest formula of the compound will be

A

$A_2 B$

B

$A B_2$

C

$A B$

D

$A B_3$

3
WB JEE 2026
MCQ (Single Correct Answer)
+1
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The plot of radial probability density( $4 \pi r^2 R^2$ )against $r$ for an electron in $n p$ orbital of a many electron atom is given below.

WB JEE 2026 Chemistry - Atomic Structure Question 1 English

The value of $n$ is

A

2

B

3

C

4

D

5

4
WB JEE 2026
MCQ (Single Correct Answer)
+1
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A buffer solution contains 100 ml of $0.01(\mathrm{M}) \mathrm{CH}_3 \mathrm{COOH}$ and 200 ml of $0.02(\mathrm{M}) \mathrm{CH}_3 \mathrm{COONa}_a .700 \mathrm{ml}$ of water is added subsequently to the buffer solution.The pH before and after dilution are [given,$p K_a=4.74 ; \log 2=0.301$ ]

A

$5.04,5.04$

B

$5 \cdot 04,0 \cdot 504$

C

$5 \cdot 04,1 \cdot 54$

D

$5 \cdot 34,5 \cdot 34$