For each strong base solution, determine [OH-], [H3O+], pH, and pOH. a. 0.15 M NaOH b. 1.5 * 10-3 M Ca(OH)2 c. 4.8 * 10-4 M Sr(OH)2 d. 8.7 * 10-5 M KOH

When dealing with strong bases in aqueous solutions, an important concept is the hydroxide ion concentration, denoted as \( [OH^-] \). Strong bases fully dissociate in water, releasing hydroxide ions. The concentration of these ions is crucial as it directly affects the solution's basicity.

For instance, if you have a monobasic base like NaOH or KOH, the \( [OH^-] \) equals the molarity of the base because each formula unit releases one hydroxide ion. However, for dibasic bases like Ca(OH)_2 or Sr(OH)_2, the situation is a bit different. Each formula unit releases two hydroxide ions, so you must multiply the molarity by two to find the \( [OH^-] \). This calculation becomes the first step in understanding how the base will interact in a solution and sets the foundation for further calculations regarding acidity and basicity.

The hydronium ion concentration, represented as \( [H_3O^+] \), is a measure of the acidity of a solution. It inversely correlates with the hydroxide ion concentration because of the self-ionization of water. In a solution, an increase in \( [OH^-] \) results in a corresponding decrease in \( [H_3O^+] \).

To calculate the \( [H_3O^+] \) in the context of strong bases, we look at the ion product constant of water \( (K_w) \) at 25°C, which is \( 1.0 * 10^{-14} \). By dividing \( K_w \) by the calculated \( [OH^-] \), we obtain the concentration of hydronium ions. This value is pivotal as it allows us to determine how acidic or basic a solution is, which is vital in many chemical processes and reactions.

Understanding the relationship between pH and pOH is essential for comprehending the acidity or basicity of a solution. The pH scale is a measure of acidity, while the pOH scale measures basicity. They are logarithmic scales based on the concentration of hydronium ions and hydroxide ions, respectively.

To calculate pOH, you use the negative logarithm of the hydroxide ion concentration: \( pOH = -\log[OH^-] \). The pH can then be found using the relationship \( pH + pOH = 14 \) at 25°C. This simple yet powerful equation reflects the inverse relationship between the pH and pOH and always adds up to 14 in pure water. These calculations are the cornerstone for understanding the pH level of any solution and are used ubiquitously in chemistry and biochemistry.

The ion product of water \( (K_w) \) is a fundamental concept in acid-base chemistry that represents the equilibrium constant for the self-ionization of water. At 25°C, this constant has a value of \( 1.0 * 10^{-14} \). This product of the concentrations of hydronium ions and hydroxide ions in water is always constant, regardless of the changes in concentration of either due to the addition of acids or bases.

For any aqueous solution, the product of \( [H_3O^+] \) and \( [OH^-] \) must equal \( K_w \). Thus, by knowing the concentration of one of these ions, we can easily calculate the other. This ion product concept is instrumental when working out the pH, pOH, or finding the concentration of the opposite ions in a given solution and is especially useful in neutralization reactions and in predicting the behavior of solutions.