J.R. S. answered 04/18/21
Ph.D. University Professor with 10+ years Tutoring Experience
Molecular equation: (NH4)2CO3(aq) + BaCl2(aq) ==> 2NH4Cl(aq) + BaCO3(s)
Complete ionic equation: 2NH4+(aq) + CO32-(aq) + Ba2+(aq) + 2Cl-(aq) => 2NH4+(aq) + 2Cl-(aq) + BaCO3(s)
ANSWER would be (c) 2NH4+(aq)
Note: It isn't (a) because there are 2 Cl-(aq) not 1