what about HCN, HCLO4, H2SO4 , are they strong acids or weak
H2SO3 SORRY
How can you tell? Look them up in a set of Ka (or Kb for strong bases) tables. Weak acids have a Ka. Strong acids do not.
HClO4 is strong. The first H of H2SO4 is strong (the second one is k2 = about 1E-2). H2SO3 is weak (both H), HCN is weak.
To determine if a substance is a strong acid or weak acid, we need to consider its dissociation behavior in water. Strong acids completely dissociate into ions when dissolved in water, while weak acids only partially dissociate.
Let's analyze each of the compounds you mentioned:
1. HCN (Hydrocyanic acid): This is a weak acid. It partially dissociates into H+ and CN- ions when dissolved in water. The dissociation reaction can be represented as follows:
HCN ⇌ H+ + CN-
2. HClO4 (Perchloric acid): This is a strong acid. It fully dissociates into H+ and ClO4- ions when dissolved in water. The dissociation reaction can be represented as follows:
HClO4 → H+ + ClO4-
3. H2SO4 (Sulfuric acid): This is also a strong acid. It completely dissociates into 2 H+ and SO4^2- ions when dissolved in water. The dissociation reaction can be represented as follows:
H2SO4 → 2 H+ + SO4^2-
So, HCN is a weak acid, while HClO4 and H2SO4 are strong acids.