Question

Given the following Ka's:

• Ka(HF) = 7.2x10⁻⁴
• Ka(HC₂H₃O₂) = 1.8x10⁻⁵
• Ka(HClO) = 3.5x10⁻⁸
• Ka(HCN) = 4.0x10⁻¹⁰
determine the equilibrium constant for each reaction and indicate whether a single or double arrow would be more appropriate. You may save some time by inputting your answer using the values in exponential format and a divide by sign "/". For example, if calculating the K involves taking 3.5x10-8 and dividing by 4.0x10-10, simply input "3.5e-8/4e-10" into the webassign answer blank.

Answer 1

The equilibrium constant for weak acids such as HF, HC₂H₃O₂, HClO, and HCN is indicated by their respective Ka values; for these reactions, double arrows are appropriate to depict the reversible establishment of equilibrium.

Step-by-step explanation:

The equilibrium constants (Ka) are given for different weak acids, and the question asks to determine the appropriate equilibrium constant for each reaction and indicate whether a single or double arrow would be more appropriate. For example, the equilibrium constant (K) for the dissociation of hydrofluoric acid (HF) into H+ and F- ions is 7.2x10⁻⁴. To illustrate the reaction, a single arrow would be used for strong acids, while a double arrow is more suitable for weak acids, indicating that the reaction does not go to completion and is establishing an equilibrium.

For acetic acid (HC₂H₃O₂), the reaction can be represented as HC₂H₃O₂ in equilibrium with H+ and C₂H₃O₂⁻ ions. Given the Ka value of 1.8x10⁻⁵, a double arrow is appropriate. Similarly, for hypochlorous acid (HClO), with Ka at 3.5x10⁻⁸, and hydrogen cyanide (HCN) with Ka at 4.0x10⁻¹⁰, double arrows would also be appropriate, highlighting the reversible nature of weak acid ionization in aqueous solution.