what is NADH+H⁺

NAD+ (Nicotinamide adenine dinucleotide) is an electron carrier which is involved in respiration. It accepts electrons from other molecules and form NADH which carries the electrons to the electron transport chain. So, the reaction is as follows:

 RH₂ + NAD⁺ -------> NADH + H⁺ + R

During this reaction, the molecule RH₂ donates electrons to NAD⁺, which gets reduced to form NADH and one H⁺ is released in the process. So, we get NADH + H⁺ when some compound donates electrons to NAD⁺.