1
JEE Main 2024 (Online) 6th April Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

Which of the following material is not a semiconductor.

A
Copper oxide
B
Graphite
C
Silicon
D
Germanium
2
JEE Main 2024 (Online) 5th April Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

The correct statements from the following are :

(A) The decreasing order of atomic radii of group 13 elements is $$\mathrm{Tl}>\mathrm{In}>\mathrm{Ga}>\mathrm{Al}>\mathrm{B}$$.

(B) Down the group 13 electronegativity decreases from top to bottom.

(C) $$\mathrm{Al}$$ dissolves in dil. $$\mathrm{HCl}$$ and liberates $$\mathrm{H}_2$$ but conc. $$\mathrm{HNO}_3$$ renders $$\mathrm{Al}$$ passive by forming a protective oxide layer on the surface.

(D) All elements of group 13 exhibits highly stable +1 oxidation state.

(E) Hybridisation of $$\mathrm{Al}$$ in $$[\mathrm{Al}(\mathrm{H}_2 \mathrm{O})_6]^{3+}$$ ion is $$\mathrm{sp}^3 \mathrm{d}^2$$.

Choose the correct answer from the options given below :

A
(A), (B), (C) and (E) only
B
(C) and (E) only
C
(A), (C) and (E) only
D
(A) and (C) only
3
JEE Main 2024 (Online) 5th April Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

The number of neutrons present in the more abundant isotope of boron is '$$x$$'. Amorphous boron upon heating with air forms a product, in which the oxidation state of boron is '$$y$$'. The value of $$x+y$$ is _________ .

A
9
B
6
C
4
D
3
4
JEE Main 2024 (Online) 1st February Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
Given below are two statements :

Statement (I) : $\mathrm{SiO}_2$ and $\mathrm{GeO}_2$ are acidic while $\mathrm{SnO}$ and $\mathrm{PbO}$ are amphoteric in nature.

Statement (II) : Allotropic forms of carbon are due to property of catenation and $\mathrm{p} \pi-\mathrm{d} \pi$ bond formation.

In the light of the above statements, choose the most appropriate answer from the options given below :
A
Statement I is false but Statement II is true
B
Both Statement I and Statement II are false
C
Both Statement I and Statement II are true
D
Statement I is true but Statement II is false
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