H[+] + OH[-] = H2O
Na[+] + OH[-] + H[+] + NO3[-] = Na[+] + NO3[-] + H2O
NaOH + HNO3 = NaNO3 + H2O
Cu[2+] + S[2-] = CuS↓
Cu[2+] + 2Cl[-] + 2K[+] + S[2-] =2K[+] + 2Cl[-] + CuS↓
CuCl2 + K2S =2KCl + CuS↓
2H[+] + CO3[2-] = CO2↑ + H2O
2Na[+] + CO3[2-] + 2H[+] + 2Cl[-]
= 2Na[+] + 2Cl[-] + CO2↑ + H2O
Na2CO3 + 2HCl = 2NaCl + CO2↑ + H2O