Predict whether aqueous solutions of the following substances are acidic, basic, or neutral: (d) 3CH3NH34NO3

Verified step by step guidance

1. Identify the cation and anion in the compound 3CH3NH3NO3. The cation is CH3NH3+ (methylammonium ion) and the anion is NO3- (nitrate ion).
2. Determine the nature of the cation CH3NH3+. Methylammonium is a derivative of ammonia (NH3), which is a weak base. The conjugate acid of a weak base (CH3NH3+) is typically a weak acid.
3. Assess the nature of the anion NO3-. Nitrate is the conjugate base of nitric acid (HNO3), which is a strong acid. The conjugate base of a strong acid is neutral in water.
4. Combine the effects of the cation and anion in solution. Since the cation (CH3NH3+) acts as a weak acid and the anion (NO3-) is neutral, the overall solution is expected to be slightly acidic.
5. Conclude that the aqueous solution of 3CH3NH3NO3 is acidic due to the presence of the weakly acidic cation.

Key Concepts

Acid-Base Theory

Acid-base theory explains the behavior of substances in terms of their ability to donate protons (H+) or accept protons. According to the Brønsted-Lowry theory, acids are proton donors, while bases are proton acceptors. Understanding this concept is crucial for predicting the pH of solutions formed by different substances.

Ammonium Compounds

Ammonium compounds, such as CH3NH3NO3, contain the ammonium ion (NH4+), which can act as a weak acid in solution. When dissolved in water, ammonium ions can donate protons, leading to an increase in the concentration of H+ ions, thus making the solution acidic. Recognizing the behavior of ammonium ions is essential for determining the acidity of the solution.

pH Scale

The pH scale measures the acidity or basicity of a solution, ranging from 0 (very acidic) to 14 (very basic), with 7 being neutral. A solution with a pH less than 7 is considered acidic, while a pH greater than 7 is basic. Understanding the pH scale is vital for predicting the nature of solutions formed by different chemical substances.