Concept:Acids turn blue litmus red and do not affect red litmus or phenolphthalein. Bases turn red litmus blue and make phenolphthalein pink. Neutral substances cause no change in either litmus or phenolphthalein.
Explanation:Test tube A has glucose solution – it is neutral. Blue litmus stays blue, red litmus stays red, phenolphthalein stays colourless. So statement (i) is false because it shows red litmus turning blue and phenolphthalein turning pink.
Test tube B has turmeric solution – it is also neutral. Same observations as A: blue litmus stays blue, red litmus stays red, phenolphthalein colourless. Statement (ii) says blue litmus turns red – that is false.
Test tube C has detergent solution – it is basic. Blue litmus remains blue, red litmus turns blue, phenolphthalein turns pink. Statement (iii) matches exactly.
Test tube D has pure water – neutral. Blue litmus stays blue, red litmus stays red, phenolphthalein colourless. Statement (iv) says red litmus turns blue – false.
Only statement (iii) is fully correct.
Answer:D. Only statement (iii) is correct.