A galvanic cell employs the reaction Mg2+(aq) + Cu(s) → Mg(s) + Cu2+(aq) and NaNO3 is the salt used in the salt bridge. During t

The interaction between calcium carbonate and hydrochloric acid can be represented by the chemical equation,

    CaCO3 + 2HCl --> CaCl2 + H2O + CO2

Calcium carbonate has a molecular weight of 100 g/mol, while hydrochloric acid's molecular weight is 36.45 g/mol. According to the equation, 100 g of calcium carbonate reacts with 72.9 g of hydrochloric acid.

    x = (4 g HCl)(100 g CaCO3 / 72.9 HCl)
      x = 5.49 g

Final result: 5.49 g

The mass of KBr required is 16.7 g. This concludes from a volume of 0.400 L and a concentration of 0.350 M. Utilizing the molarity formula, moles are calculated as 0.14, leading to a molecular weight calculation of 119 g/mol, thus resulting in a mass of 16.7 g of KBr.

Answer:NH₃/NH₄Cl

Explanation:

The pH of a buffer can be determined using Henderson-Hasselbalch's equation.

When the concentration of acid equals that of the base, the pH aligns with the pKa of the buffer. The ideal pH range is pKa ± 1.

Below are the buffers and their corresponding pKa values:

• CH₃COONa/CH3COOH (pKa = 4.74)

• NH₃/NH₄Cl (pKa = 9.25)

• NaOCl/HOCl (pKa = 7.49)

• NaNO₂/HNO₂ (pKa = 3.35)

• NaCl/HCl Not a buffer

Thus, the ideal buffer is NH₃/NH₄Cl.