Half-life: first order vs zero orderअर्धायु: प्रथम कोटि बनाम शून्य कोटिHalf-life: first order vs zero order

Class 12 Chemistry · Chapter 3 · interactive diagram

Parts and what they mean

• First order: exponential decay (प्रथम कोटि: चरघातांकी क्षय) — [R] = [R]₀e^(−kt). Never exactly reaches zero.
• First order: every half-life is the same (प्रथम कोटि: हर अर्धायु बराबर) — t½ = 0.693/k, independent of [R]₀: 1 → ½ → ¼ → ⅛ in equal times.
• Zero order: straight-line fall (शून्य कोटि: सीधी रेखा में गिरावट) — [R] = [R]₀ − kt; it reaches zero at t = [R]₀/k.
• Zero order: each successive half-life is half the previous one (शून्य कोटि: हर अगली अर्धायु पिछली की आधी) — t½ = [R]₀/2k ∝ [R]₀: as concentration halves, t½ halves too.
• Concentration vs time (सांद्रता बनाम समय) — Half-life = time for [R] to fall to half its initial value.

Original diagram drawn by Simple Learning Hub, based on the NCERT textbook. Report a mistake