Answer:
The correct answer is
B.action potential; sodium
Explanation:
Action potential
Nerve action potentials are initiated and propagated in an all or nothing fashion. The all-or nothing action potential is initiated when the membrane potential threshold value is reached
Sodium
Voltage-gated Na⁺ ions membrane channels open enabling an influx of sodium ions to rapidly enter the cell, raising the membrane potential up to +40 mV
Depolarization in the neuron is based ion exchange channels opening to allow the rapid influx of sodium ions (Na⁺) and the efflux of potassium ions (K⁺)
The neuronal responds rapidly and for short periods to the activation of an ion channel receptor by a drug or natural neurotransmitter is rapid rel
I think the correct answer is the first option. It has nonpolar bonds and a symmetrical structure. The structure of a BF3 molecule shows a symmetrical trigonal geometry. The net dipole moment of the molecule is zero therefore it is polar.
<u>Answer:</u> The correct answer is Option C.
<u>Explanation:</u>
Net ionic equation of any reaction does not include any spectator ions.
Spectator ions are defined as the ions which does not get involved in a chemical equation. They are found on both the sides of the chemical reaction when it is present in ionic form.
The chemical equation for the reaction of sodium bicarbonate and acetic acid is given as:

Ionic form of the above equation follows:

As, sodium and acetate ions are present on both the sides of the reaction. Thus, it will not be present in the net ionic equation and are spectator ions.
The net ionic equation for the above reaction follows:

Hence, the correct answer is Option C.
B and D is out. It cant be A because heat of combustion is substance not compound. So the answer is D.