UHS MDCAT 2024 Chemistry#Aldehydes and Ketones#Nucleophilic Addition1226Choose the best answerReaction of HCN with formaldehyde is a:ANucleophilic addition reactionBNucleophilic substitution reactionCElectrophilic addition reactionDElectrophilic substitution reaction Like 1 Discuss 0Share
Chemical KineticsRate Law from Reaction Mechanism1227Choose the best answerConsider the mechanism: Step 1: 2NO ⇌ N₂O₂ (fast equilibrium) Step 2: N₂O₂ + H₂ → N₂O + H₂O (slow) Step 3: N₂O + H₂ → N₂ + H₂O (fast) The overall rate law is:ARate = k[NO]²[H₂]BRate = k[N₂O₂][H₂]CRate = k[NO]²DRate = k[N₂O₂][H₂]² Like 0 Discuss 0Share
Chemical KineticsPromoters and Activators1228Choose the best answerA substance that increases the activity of a catalyst is called:AActivatorBPromoterCCatalyst poisonDBoth A and B Like 0 Discuss 0Share
StoichiometryMole Concept and Avogadro Constant1229Choose the best answerHow many molecules are present in 22 g CO₂?A6.022 × 10²³B3.011 × 10²³C6.023 × 10²¹D6.023 × 10²² Like 0 Discuss 0Share
MDCAT Chemistry Past Papers Reconduct 2023#Limiting Reagent#Stoichiometry1230Choose the best answerTo obtain the maximum amount of product in a balanced chemical reaction, which concept should be utilized? (MDCAT Reconduct 2023)AStoichiometryBActual yieldCTheoretical yieldDExcess reactant Like 0 Discuss 0Share