Which reaction is an example of an oxidation-reduction reaction?

1. agno₃+ki→agi+kno₃
2. cu+2agno₃→cu(no₃)₂+2ag
3. 2koh+h₂so₄→k₂so₄+2h₂o
4. ba(oh)₂+2hcl→bacl₂+2h₂o

Who is better, messi or cristiano, i need this for a chemistry class. asap

Explain why pure hydrogen cyanide does not conduct electricity, but become a conductor when it is dissolved in water? (at room temp, pure hcn exists as a volatile liquid)

Which statement correctly identifies the scientific question and describes why the question is scientific? question 1 refers to the supernatural.question 2 reflects a moral or social value.question 3 refers to something that can be measured.question 4 reflects a question that can’t be observed.