The d- and f- Block Elements Online Objective Test | The d- and f- Block Elements Online Objective Test

# The d- and f- Block Elements # CBSE 12TH CHEMISTRY Prepare / Learn

Q1. How many carats are in 87.5% gold?

A. 18

B. 21

C. 24

D. 15

Answer : Option B
Explaination / Solution:

\begin{matrix} K a r a t = 24 \times (\frac{M_{g}}{M_{m}}) \\ M_{g} = 87.5 a n d M_{m} = 100 \end{matrix}

# The d- and f- Block Elements # CBSE 12TH CHEMISTRY Prepare / Learn

Q2. How many d – block elements have ability to evolve hydrogen gas from 2% nitric acid?

A. 2

B. Many

C. 3

D. 1

Answer : Option A
Explaination / Solution:

Both Zn and Fe can displsce Hydrogen from

H N O_{3}

# The d- and f- Block Elements # CBSE 12TH CHEMISTRY Prepare / Learn

Q3. Haemoglobin and chlorophyll contain

A. Fe and Mn

B. Mg and Fe

C. Fe and Co

D. Fe and Mg

Answer : Option D
Explaination / Solution:

Hb contains Fe and Chlorophyll contains Mg.

# The d- and f- Block Elements # CBSE 12TH CHEMISTRY Prepare / Learn

Q4. Which chromium compound is widely used in tanning of leather?

C r O_{2} C l_{2}

C r C l_{3}

\begin{array}{l} K_{2} S O_{4} . C r_{2} {(S O_{4})}_{3} .24 H_{2} O \end{array}

C r_{2} O_{3}

Answer : Option C
Explaination / Solution:

K_{2} S O_{4} . C r_{2} {(S O_{4})}_{3} .24 H_{2} O

is used in taaning of leather.

# The d- and f- Block Elements # CBSE 12TH CHEMISTRY Prepare / Learn

Q5. The production of oxidation of

I^{-}

with

M n {O_{4}}^{-} -

in acidic medium is

I O^{-} -

I {O_{3}}^{-} -

I_{2}

I {O_{4}}^{-} -

Answer : Option C
Explaination / Solution:

In acidic medium

I^{-}

oxidizes to

I_{2}

# The d- and f- Block Elements # CBSE 12TH CHEMISTRY Prepare / Learn

Q6. In dilute alkaline solution,

M n {O_{4}}^{-} -

changes to

M n {O_{4}}^{2 -}

M n_{2} O_{3}

M n O_{2}

M n O_{2}

M n O_{2}

Answer : Option D
Explaination / Solution:

In alkaline medium

M n O_{2}

is forms as a result of reduction of

M n {O_{4}}^{-}

# The d- and f- Block Elements # CBSE 12TH CHEMISTRY Prepare / Learn

Q7. Which shows maximum magnetic moment among the bivalent ions of the first transition series?

F e^{2 +}

M n^{2 +}

N i^{2 +}

C o^{2 +}

Answer : Option B
Explaination / Solution:

M n^{2 +}

has d5 configuration so maximum no. of un paired electrons.

# The d- and f- Block Elements # CBSE 12TH CHEMISTRY Prepare / Learn

Q8. Which is called chromic acid?

C r_{3} O_{4}

C r_{2} O_{3}

C r O_{3}

Answer : Option C
Explaination / Solution:

C r O_{3}

is chromic oxide.

# The d- and f- Block Elements # CBSE 12TH CHEMISTRY Prepare / Learn

Q9. Which one of the following combines with

F e 2 +

ion to form a brown complex?

N 2 O 3

N 2 O 5

N 2 O

Answer : Option B
Explaination / Solution:

[F e (H 2 O) 5 N O] 2 +

is brown color complex.

# The d- and f- Block Elements # CBSE 12TH CHEMISTRY Prepare / Learn

Q10. Lucas reagent is

H 2 S O 4 + H C l

N O + H 2 O

M n O 2 + H 2 O

Z n C l 2 + H C

Answer : Option D
Explaination / Solution:

Lucas Test is done to distinguish primary secondary and tertiary alcohols. Lucas reagent is

Z n C l 2 + H C l

Total Question/Mark :
Scored Mark :
Mark for Correct Answer : 1
Mark for Wrong Answer : -0.5
Mark for Left Answer : 0

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