Predict the stronger acid in each pair: (a) HNO3 or HNO2 (b) H2SO4 or H2SeO4 (c) CH3COOH or CCl3COOH.

Verified step by step guidance

1. Step 1: Understand the concept of acid strength. Acid strength is determined by the ability of an acid to donate a proton (H+). The more easily an acid donates a proton, the stronger it is.
2. Step 2: Analyze the molecular structure and electronegativity for each pair. For (a) HNO3 vs. HNO2, consider the number of oxygen atoms and their effect on the stability of the conjugate base. More oxygen atoms generally stabilize the conjugate base through resonance, making the acid stronger.
3. Step 3: For (b) H2SO4 vs. H2SeO4, compare the central atoms (S vs. Se). Sulfur is more electronegative than selenium, which can lead to a stronger acid due to better stabilization of the conjugate base.
4. Step 4: For (c) CH3COOH vs. CCl3COOH, examine the effect of substituents on the carboxylic acid group. The presence of electronegative chlorine atoms in CCl3COOH increases the acid strength by stabilizing the conjugate base through inductive effects.
5. Step 5: Conclude by identifying the stronger acid in each pair based on the analysis of molecular structure, electronegativity, and resonance or inductive effects.