Assertion : Monoclinic sulphur is an example of monoclinic crystal system.

Reason : For a monoclinic system, $a
e b
e c$ and $\alpha = \gamma = 90°$, $\beta
e 90°$.

(a) Assertion is true but Reason is false.
(b) Both Assertion and Reason are true and Reason is the correct

Question

Assertion : Monoclinic sulphur is an example of monoclinic crystal system.

Reason : For a monoclinic system, $a 
e b 
e c$ and $\alpha = \gamma = 90°$, $\beta 
e 90°$.

(a) Assertion is true but Reason is false.
(b) Both Assertion and Reason are true and Reason is the correct explanation of Assertion.
(c) Both Assertion and Reason are false.
(d) Both Assertion and Reason are true, but Reason is not the correct explanation of Assertion.

Accepted Answer

> [!TLDR]
> Monoclinic sulphur is a genuine example of the monoclinic crystal system, and the reason correctly states that system's defining unequal edge lengths and single non-90° angle — both true, and the reason correctly explains the assertion.
>
> Seven crystal systems are classified by their unit-cell edge lengths ($a,b,c$) and inter-axial angles ($\alpha,\beta,\gamma$). The monoclinic system is defined by $a
e b
e c$ (three unequal edges) and $\alpha=\gamma=90°$, $\beta
e90°$ (two right angles and one oblique angle) — exactly as the reason states, so the reason is a true and accurate statement of the general monoclinic system's parameters. Monoclinic sulphur (one of the allotropic crystalline forms of sulphur, stable above 96°C, alongside rhombic sulphur) is a standard textbook example of a substance crystallising in this monoclinic system, so the assertion is also true. Since the reason directly and correctly …

Q.Assertion : Monoclinic sulphur is an example of monoclinic crystal system. Reason : For a monoclinic system, $a \ne b \ne c$ and $\alpha = \gamma = 90°$ , $\beta \ne 90°$ .

Concept understanding — Unit Cell Types — Primitive, Non-Primitive and the Seven Crystal Systems

Q.Assertion : Monoclinic sulphur is an example of monoclinic crystal system. Reason : For a monoclinic system, a≠b≠ca \ne b \ne ca=b=c and α=γ=90°\alpha = \gamma = 90°α=γ=90°, β≠90°\beta \ne 90°β=90°.

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Q.Assertion : Monoclinic sulphur is an example of monoclinic crystal system. Reason : For a monoclinic system, $a \ne b \ne c$ and $\alpha = \gamma = 90°$ , $\beta \ne 90°$ .

Unlock everything free for 14 days