Solved UPSC CDS/OTA Question
A solved UPSC CDS/OTA PYQ — decoded step-by-step.
Solve it the standard way once — then learn the shortcut.
Q · Soap and DetergentsMedium · 45s
Which of the following can increase the lathering ability of soap?
TopicSoap and Detergents
Question Typemultiple choice
DifficultyMedium
Marking+1 / −0.33
Test Duration30 min
Step-by-Step Solution
The complete worked solution.
Every step explained — no skipped algebra.
Soft water does not have Ca²⁺/Mg²⁺ ions that cause scum.
Final Answer: Option B — Soft water