Which statement correctly relates two substances from this reaction? h2co3 + h2o ⇌ h3o+ + hco3− a. hco3− is the conjugate acid of h2co3. b. h2o is the conjugate base of h2co3. c. h3o+ is the conjugate acid of h2o. d. h2co3 is the conjugate base of h3o+

We have to know which two substances are related correctly.

The correct answer is: (C) H₃O⁺ is the conjugate acid of H₂O.

In an acid-base reaction, an acid reacts with a base and gives a conjugate base and conjugate acid. The reaction is shown below:

Acid₁ + Base₂ ⇄ Conjugate Base₁ + Conjugate Acid₂

In the reaction H₂CO₃ + H₂O ⇌ H₃O⁺ + HCO₃⁻, H₂CO₃  is an acid because it releases H⁺ ion and converts to HCO₃⁻. Here HCO₃⁻ is the conjugate base of H₂CO₃ ( according Arrhenius theory).

H₂O accepts H⁺ ion and is converted to H₃O⁺ , thus H₂O behaves as Bronsted base. So, H₃O⁺ is the conjugate acid of Bronsted base H₂O.

Hence, the correct answer is: (C) H₃O⁺ is the conjugate acid of H₂O.

1. for the first question, we must find the mass of the anhydrous salt, mgso₄. the molar mass for mgso₄·7h₂o is 246.47 g/mol, while that of mgso₄ is 120.37 g/mol.7.834 g mgso₄·7h₂o * 1 mol mgso₄·7h₂o/246.47 g * 1 mol mgso₄/1 mol mgso₄·7h₂o * 20.37 g mgso₄/mol = 0.647 g mgso₄

2. mass of water = mass of sample - mass of anhydrous salemass of water = 7.834 - 0.647 = 7.19 gpercent water in hydrate = 7.19/7.834 * 100 = 91.74%