Direction: Four substances were tested for their electrical conductivity. The results are shown in the table. Study the table and answer the following questions. Substance Bulb Substance at Cathode Substance at Anode P Lights up Aluminium Oxygen Q Lights up Nothing Nothing R Does not light up Nothing Nothing S Lights up Hydrogen Carbon dioxide Which solutions could be alumina and magnesium nitrate respectively?

• A.  P and Q
• B.  R and Q
• C. Displacement 
• D.  P is the alumina but no one is magnesium nitrate.