AP Chemistryhardmcq1 pt
What is the oxidation number of hydrogen in CaH₂?
A.−1
B.+1
C.0
D.+2
Explanation
Core Concept
In metal hydrides, hydrogen takes −1 (the exception to its usual +1). Calcium's +2 forces each hydrogen to −1 to sum to zero.
Correct Answer
A−1
More Unit 4: Chemical Reactions practice questions
- easyWhat is the oxidation number of carbon in CO₃²⁻?
- mediumHow many grams of HCl (36.5 g/mol) react completely with 4.0 g of NaOH (40.0 g/mol)?
- easyIn 4Fe + 3O₂ → 2Fe₂O₃, which element is reduced?
- easyWhich observation is evidence of a physical change only?
- medium2.0 mol of N₂ and 2.0 mol of H₂ react via N₂ + 3H₂ → 2NH₃. How many moles of H₂ remain after complete reaction?
Practice more AP Chemistry questions with full explanations
Practice Unit 4: Chemical Reactions Questions →