Out of the following compounds, which one is the weakest base? NH3, CH3NH2, NH2F, NH2Br
To determine the weakest base among the given compounds (NH3, CH3NH2, NH2F, NH2Br), we need to compare their basicity. The basicity of a compound depends on its ability to donate an electron pair.
One way to compare the basicity of these compounds is by considering the electronegativities of the atoms bonded to the central nitrogen atom. Generally, as electronegativity increases, the electron density on the nitrogen atom decreases, resulting in a weaker base.
Let's examine each compound:
1. NH3:
In NH3, the hydrogen atoms are bonded to nitrogen, which is less electronegative than any other atom listed. Therefore, NH3 is the strongest base among the given compounds.
2. CH3NH2:
In CH3NH2, the nitrogen atom is bonded to one hydrogen atom and three carbon atoms. Carbon is more electronegative than hydrogen but less electronegative than some other atoms on the list. Thus, CH3NH2 is weaker than NH3 but stronger than the remaining compounds.
3. NH2F:
In NH2F, the nitrogen atom is bonded to one hydrogen atom and one fluorine atom. Fluorine is significantly more electronegative than carbon, making the electron density on nitrogen lower compared to CH3NH2. Hence, NH2F is weaker than both NH3 and CH3NH2.
4. NH2Br:
In NH2Br, the nitrogen atom is bonded to one hydrogen atom and one bromine atom. Bromine is less electronegative than fluorine but more electronegative than carbon. Therefore, NH2Br is weaker than NH3 and CH3NH2 but stronger than NH2F.
Therefore, based on increasing order of basicity, the correct answer is:
NH2F < NH2Br < CH3NH2 < NH3