The lime is called as poor lime when % of clay is
- A0%
- B< 30%
- C>30%Correct
- D>70%
Solution
Concept
Poor lime (lean lime) contains more than 30% clay as impurity.
Step-by-step solution
1. Lime is classified by the amount of clay and other impurities. 2. Fat lime has very little clay (less than 5% impurities). 3. Poor or lean lime contains more than 30% clay. 4. So the answer is (C) >30%.
Explanation
Poor lime has a lot of clay, more than 30%. It slakes very slowly and sets poorly. It is used only for low-quality mortar.
Why the other options are wrong
A: 0% clay means very pure lime, which is fat lime. B: Less than 30% clay fits fat or hydraulic lime, not poor lime. D: More than 70% is not the standard limit. Poor lime is defined as more than 30%.
Shortcut
Poor lime = more than 30% clay.
Common mistake
Taking the 5% impurity limit of fat lime as the limit for poor lime.
Correct answer: C) >30%