Explanation

BF3 (boron trifluoride) is not a nucleophile.

It is a Lewis acid, meaning it accepts electron pairs during reactions rather than donating them.

A nucleophile is a species (atom or group of atoms) that donates a pair of electrons to form a new covalent bond.

Nucleophiles are often negatively charged or have lone pairs of electrons that can be used for bonding.

• H2O (water)
• H2S (hydrogen sulfide)
• NH2

Explanation

The stamen is the male reproductive organ.

It consists of a pollen anther and a long supporting filament.

Explanation

Straight-four engines typically use a firing order of 1-3-4-2,

 some British engines use a firing order of 1-2-4-3.

Flat-four engines typically use a firing order of R1-R2-L1-L2.

Straight-five engines typically use a firing order of 1-2-4-5-3

Explanation

The wavelength of the radiation emitted when an electron in a hydrogen atom jumps from a higher orbit (n = 2) to a lower orbit (n = 1) can be calculated using the Rydberg formula:

Explanation

Adrenaline (also known as epinephrine) is hydrolyzed by the enzyme monoamine oxidase (MAO).

Explanation

Aerobic respiration produces energy more efficiently and faster than anaerobic respiration.

Explanation

The cells contained in the lacunae of the bone are called osteocytes.

Explanation

The diffusion of sodium ions across the postsynaptic membrane causes it to depolarize, initiating a new action potential.

Explanation

Chewing or mastication is the process by which food is crushed and ground by teeth.

It is the first step of digestion,

and it increases the surface area of foods to allow a more efficient breakdown by enzymes.

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ND17-1-2023

Explanation

Substitution reactions are given by alkanes whereas unsaturated hydrocarbons like alkenes and alkynes undergo addition reactions.