Why is ammonia a nucleophile

This means the sum of the energies of the products is lower than the sum of the energies of reactants, so the reaction is spontaneous. Sign up to join this community.

The best answers are voted up and rise to the top. Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Learn more. Asked 5 years, 2 months ago. Active 5 years, 2 months ago. Viewed 6k times. Improve this question. K-Feldspar K-Feldspar 2, 9 9 gold badges 35 35 silver badges 61 61 bronze badges. Add a comment. In this regard, is water or ammonia a better Nucleophile?

Ammonia still has a lone pair and it is a pretty good nucleophile. We don't need a negative charge on the nitrogen for it to displace a halogen from an alkyl halide. Because nitrogen is a litle less electronegative than oxygen, ammonia is a better nucleophile than water.

Ammonia is nucleophilic , but it is also basic. In an ammonium ion, nitrogen is bonded to hydrogen atoms and shares electrons with them.

This causes all the orbitals to be fully filled and hence, nitrogen does not have space for any additional electrons. Thus, the ammonium ion is not an electrophile. NH3 Ammonia has the stronger nucleophilic character than water molecule. Coz the Oxygen in the water molecule doesn't likely to bond with any carbon atom compared to Nitrogen atom.

Since Oxygen has more electronegativity than Nitrogen. Hence it holds onto its lone pair tightly than Nitrogen. You couldn't heat this mixture under reflux, because the ammonia would simply escape up the condenser as a gas. There is then the possibility of a reversible reaction between this salt and excess ammonia in the mixture.

The ammonia removes a hydrogen ion from the ethylammonium ion to leave a primary amine - ethylamine. A nucleophile is a reactant that provides a pair of electrons to form a new covalent bond. But it has a lone pair of electrons. What makes a nucleophile strong? What Makes A Good Nucleophile? If you read the last post, you'll recall that a nucleophile is a species that donates a pair of electrons to form a new covalent bond. Is ammonia a strong or weak nucleophile?

The nitrogen atom is joined to 4 things rather than its usual 3. Nitrogen can only join to 4 things if it carries a positive charge. Note: Nitrogen with a positive charge has the same arrangement of electrons as a carbon atom - which normally forms 4 bonds. Technically, this is known as an S N 2 reaction. S stands for substitution, N for nucleophilic, and the 2 is because the initial stage of the reaction involves two species - the bromoethane and the ammonia.

If your syllabus doesn't refer to S N 2 reactions by name, you can just call it nucleophilic substitution. Ethylammonium bromide is a salt of a primary amine and the acid, HBr.

A primary amine has the formula R-NH 2. It is primary in the sense that there is only one alkyl group attached to the nitrogen atom. Primary amines are weak bases very similar to ammonia and so form salts with acids.

At this point you need to know whether your examiners are happy for you to stop there, or want you to go a stage further to form the free primary amine. Note: You need to check the mark schemes for recent exam papers, or any support material published by your examiners. You won't be able to tell this by looking at your syllabus, or at the exam papers themselves. You can find out how to get hold of this material by visiting your examiners' web site.

If you are working to a UK-based syllabus for 16 - 18 year olds, you can find a link to this on the syllabuses page. Notice that this change is reversible. What you will end up with is a mixture of all four of the species in this last equation - together, of course, with the bromide ions formed in the first stage.

The higher the proportion of ammonia in the original reaction mixture, the greater the chance of the free ethylamine being formed. We'll talk this mechanism through with a simple tertiary halogenoalkane like the one on the right 2-bromomethylpropane.

Why do tertiary halogenoalkanes need a different mechanism? Any other approach is prevented by the halogen atom, which is both bulky and slightly negatively charged. The charge repels the incoming nucleophile. With a tertiary halogenoalkane, this approach from the back is impossible.