1. which of the following is a combination reaction?
a. 2so2 + o2—> 2so3
b. zn + cu(no3)2–> zn(no3)2 + cu
c. 2h2o2–> 2h2o+o2
d. agno3 + nacl → agcl+nano3

The answer to your question is: letter A

Explanation:

A combination reaction is when there are two reactants that gives only one product.

a. 2SO2 + O2—> 2SO3                          This is a combination reaction,

                                                               2 reactants gives one product.

b. Zn + Cu(NO3)2–>Zn(NO3)2 + Cu     This is not a combination reaction,

                                                                it's a single replacement reaction.

c. 2H2O2–> 2H2O+O2                          This is a decomposition reaction

d. AgNO3 + NaCl → AgCl+NaNO3        THis is a double replacement reaction.

Climate, Weather patterns,

Explanation: