Key Idea According to Lewis concept, "Acids are electron acceptor and bases are electron donor". Since, electron deficient compounds also have an ability to accept electrons, these are regarded as acids. 
NEET UG 2009 — Chemistry Physical Chemistry
Which of the following molecules acts as a Lewis acid?
Held on 30 Apr 2009 · Verified 9 Jul 2026.
(CH3)3 B
(CH3)2O
(CH3)3P
(CH3)3 N
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The unit of rate constant for a first-order reaction is:
For the reaction 2SO₂(g) + O₂(g) ⇌ 2SO₃(g), ΔH = -198 kJ. Which condition favours forward reaction?
The standard heat of formation, in $\mathrm{kcal} / \mathrm{mol}^{\text {of }} \mathrm{Ba}^{2+}$ is : [Given : standard heat of formation of $\mathrm{SO}_4^{2-}$ ion (aq) $=-216 \mathrm{kcal} / \mathrm{mol}$, Standard heat of crystallisation of $\mathrm{BaSO}_4(\mathrm{~s})=-4.5 \mathrm{kcal} / \mathrm{mol}$, standard heat of formation of $\left.\mathrm{BaSO}_4(\mathrm{~s})=-349 \mathrm{kcal} / \mathrm{mol}\right]$
Match List - I with List - II $\begin{array}{llll} & \begin{array}{l} \text { List-I } \\ \text { (Example) } \end{array} & & \begin{array}{l} \text { List-II } \\ \text { (Type of Solution) } \end{array} \\ \text { A. } & \text { Humidity } & \text { I. } & \text { Solid in solid } \\ \text { B. } & \text { Alloys } & \text { II. } & \text { Liquid in gas } \\ \text { C. } & \text { Amalgams } & \text { III. } & \text { Solid in gas } \\ \text { D. } & \text { Smoke } & \text { IV. } & \text { Liquid in solid } \end{array}$ Choose the correct answer from the options given below:
The conjugate base of H₂SO₄ is:
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