Answer: [tex]1.0\times 10^1[/tex] grams of calcium carbonate are needed to provide the RDA of calcium.
Explanation:
Given,
The recommended daily allowance (RDA) of calcium is = 1.2 g
Calcium present in calcium carbonate = 12.0 % by mass i.e. 12 g of calcium is present in 100 g of calcium carbonate
Thus if 12 g of calcium is provided by 100 g of calcium carbonate.
1.2 g of of calcium is provided by =[tex]\frac{100}{12}\times 1.2=10 g[/tex] of calcium carbonate.
Thus correct option is [tex]1.0\times 10^1[/tex] g
