See image — Isomerism and Stereochemistry Chemistry Question

💡 Solution & Explanation

Concept: Chirality refers to the property of an object that is non-superimposable on its mirror image. A chiral object lacks an internal plane of symmetry, axis of symmetry, or center of symmetry that would make it identical to its mirror image. Step 1 - Analyze each option: (a) Cell phone: A typical cell phone has a plane of symmetry (left-right symmetry along its vertical axis). Its mirror image is superimposable on the original. Therefore, a cell phone is achiral. (b) Spiral staircase: A spiral staircase winds either clockwise (right-handed) or counterclockwise (left-handed) as you go upward. Its mirror image would be the opposite handedness. A right-handed spiral staircase cannot be superimposed on its mirror image (a left-handed spiral staircase). There is no plane of symmetry. Therefore, a spiral staircase is chiral. (c) Scissor: A standard scissor has a plane of symmetry (the plane containing the blades and the pivot). Its mirror image is superimposable on the original. Therefore, a scissor is achiral. Step 2 - Conclusion: Only the spiral staircase is chiral among the given options because it exists as two non-superimposable mirror images (like a helix), whereas the cell phone and scissor possess planes of symmetry making them achiral. Why other options fail: - (a) Cell phone is achiral due to bilateral symmetry. - (c) Scissor is achiral due to its plane of symmetry. - (d) All of these is incorrect because only the spiral staircase qualifies. Therefore, the correct answer is B.