RP4 - Test-tube reactions - anions and cations

• Testing for cations - NH4+

  • addition of NaOH/OH– and warming (put under water bath)
  • gives gas that turns damp red litmus blue (= ammonia) showing NH4 + (water bath = warm)
• Equation for positive result of ammonium ions

  • NH4 + + OH− → NH3 + H2O