A substance either an ion or a molecule that can act either an acid or a base depending on a medium is called Amphoteric. Some metals like zinc, tin, copper and aluminium which produce either metal oxides or hydroxides are examples of amphoteric. During the Amphoterism, the metal compound acts either an acid or a base depending on their oxidation state.
Electronegativity of an element decreases as we move down a group on the periodic table and electronegativity increases while moving from left to right across a period on the periodic table.
Explanation:
- The electronegativity increases as we move from left to right across a period because from left to right across a period, the nuclear charge is increasing Hence the attraction for the valence electrons also increases.
- As we move down a group, the atoms of each element have an increasing number of energy levels. The distance between the nucleus and valence electron shell increases and reduces the attraction for valence electrons. Hence electronegativity decreases as we move from top to bottom down a group.
I think the answer is three but i can't be sure.
Bronsted - Lowry acid in the given reaction is NH₄, as it gives H⁺ ion.
<h3>What is Bronsted - Lowry acid?</h3>
According to the theory of Bronsted - Lowry, acids are those substances which gives H⁺ ion or proton in the aqueous medium.
Given chemical reaction is :
NH₄ + HPO₄²⁻ → NH₃ + H₂PO₄⁻
In the above reaction NH₄ is the Bronsted - Lowry acid as it gives H⁺ ion in the reaction and changes to NH₃ which is the conjugate base of NH₄. Whereas HPO₄²⁻ is the Bronsted - Lowry base as it accepts the H⁺ ion to form H₂PO₄⁻ which is the conjugate acid of it.
Hence, option (1) is correct, i.e. NH₄ is the Bronsted - Lowry acid.
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