Steric effects in SN2 reactionsSN2 अभिक्रियाओं में त्रिविम प्रभावSteric effects in SN2 reactions

NCERT Fig 6.3 · Class 12 Chemistry · Chapter 6 · interactive diagram

Parts and what they mean

• Methyl halide — relative rate 30 (मेथिल हैलाइड — आपेक्षिक वेग 30) — Only three small H atoms around C: the nucleophile reaches the back of carbon easily — fastest SN2.
• Ethyl (1°) halide — relative rate 1 (एथिल (1°) हैलाइड — आपेक्षिक वेग 1) — One CH₃ replaces an H: already 30 times slower.
• Isopropyl (2°) halide — relative rate 0.02 (आइसोप्रोपिल (2°) हैलाइड — आपेक्षिक वेग 0.02) — Two CH₃ groups crowd the back side.
• tert-Butyl (3°) halide — relative rate ≈ 0 (तृतीयक-ब्यूटिल (3°) हैलाइड — आपेक्षिक वेग ≈ 0) — Three bulky CH₃ groups block the approach completely: 3° halides react by SN1 instead.
• Order of SN2 reactivity (SN2 क्रियाशीलता का क्रम) — Primary > secondary > tertiary (methyl fastest) — set by steric hindrance.

Original diagram drawn by Simple Learning Hub, based on NCERT Fig 6.3. Report a mistake