Target Exam

CUET

Subject

Chemistry

Chapter

Inorganic: D and F Block Elements

Question:

Match the properties given in List-I with the metals given in List-II

List-I Property

List-II Metal

(A) 3d series element with highest melting point

(I) Os

(B) element which can show +8 oxidation state

(II) Fe

(C) 3d series element with largest number of oxidation states

(III) Cr

(D) constituent of Mischmetall

(IV) Mn

Choose the correct answer from the options given below:

Options:

(A)-(III), (B)-(I), (C)-(II), (D)-(IV)

(A)-(III), (B)-(I), (C)-(IV), (D)-(II)

(A)-(IV), (B)-(II), (C)-(I), (D)-(III)

(A)-(II), (B)-(I), (C)-(IV), (D)-(III)

Correct Answer:

(A)-(III), (B)-(I), (C)-(IV), (D)-(II)

Explanation:

The correct answer is Option (2) → (A)-(III), (B)-(I), (C)-(IV), (D)-(II)

List-I Property

List-II Metal

(A) 3d series element with highest melting point

(III) Cr

(B) element which can show +8 oxidation state

(I) Os

(C) 3d series element with largest number of oxidation states

(IV) Mn

(D) constituent of Mischmetall

(II) Fe

(A) 3d series element with highest melting point $\rightarrow$ (III) Cr (Chromium)

In the $3d$ transition series, melting points generally increase toward the middle of the series due to the involvement of a greater number of electrons from both $(n-1)d$ and $ns$ orbitals in interatomic metallic bonding. Chromium ($Cr$) has the highest melting point in the $3d$ series.

(B) Element which can show +8 oxidation state $\rightarrow$ (I) Os (Osmium)

Osmium is famous in inorganic chemistry for its ability to reach the $+8$ oxidation state, most notably in osmium tetroxide ($OsO_4$). While ruthenium also shows this state, Osmium is the classic example among the heavy transition metals.

(C) 3d series element with largest number of oxidation states $\rightarrow$ (IV) Mn (Manganese)

Manganese has the electronic configuration $[Ar] 3d^5 4s^2$. Because it has the maximum number of unpaired electrons in the $d$-subshell, it exhibits the widest range of oxidation states in the $3d$ series, ranging from $+2$ to $+7$.

(D) Constituent of Mischmetall $\rightarrow$ (II) Fe (Iron)

Mischmetall is an alloy consisting of rare earth elements (about $95\%$ Lanthanoids, mostly Cerium and Lanthanum) and about $5\%$ Iron ($Fe$), along with traces of $S$, $C$, $Ca$, and $Al$. It is commonly used in cigarette lighter flints.