Answer:
Answer 'A'
Explanation:
There are 3 acid-base theories.
- Arrhenius Theory
- Bronsted-Lowry Theory
- Lewis Theory
In the Arrhenius and the Bronsted-Lowry Theories, for an acid to be an acid two requirements must be met. That is, the substance must be soluble in water and two, undergo ionization generating a hydronium cation (H₃O⁺) and a base anion (A⁻) in process; i.e., H-Anion + H₂O => H₃O⁺ + Anion⁻.
The Lewis Theory defines acids and bases in terms of electron pair donation (the base) and electron pair acceptor (the acid). This theory does not require the presence of an ionizable hydrogen in the substance of interest, only non-bonded electron pairs (base) and a cationic character that accepts electron pairs without violating the octet rule in chemical bonding.
For the purpose of answering your question, the Arrhenius and Bronsted-Lowry theories are sufficient for defining acids and bases undergoing ionization in aqueous media. With this, one should understand also that acids and bases are classified as strong acids and strong bases (compounds that ionize 100% aqueous media) or weak acids and weak bases (compounds that do not ionize 100% in aqueous media).
Strong Acids* include HCl, HBr, HI, HNO₃, HClO₄ & H₂SO₄ (1st ionization step only). Strong Bases include Group IA and Group IIA hydroxides except for Beryllium Hydroxides. The weak acids are compounds with ionizable hydrogens that are NOT members of the strong 6 listed above. The weak bases are ammonia and ammonia derivatives in aqueous media.
It is recommended that students only need to memorize the strong six acids in that any compound not one of these six with an ionizable hydrogen is a weak acid whether you know its name or not. The weak bases, as mentioned, are ammonia and ammonia derivatives in water. These compounds will undergo coordinate bonding to generate an ionizable compound containing an ammonium cation and hydroxyl anion. The reaction is as follows:
RNH₂ + H₂O => RNH₃⁺OH⁻(aq) => RNH₃⁺(aq) + OH⁻(aq)
Typically, weak acids and weak bases undergo very limited ionization in the range of 1% to 2%. The compounds remaining are in concentrations of 98% - 99% unionized but form soluble homogeneous solutions.
If you have further questions, kick back a note. Doc
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*Some scholars include sulfurous acid (H₂SO₃) as a strong acid but analysis shows aqueous solutions - under special conditions - to contain unionized H₂SO₃ and thus violates the 100% ionization requirement.
