Question

A $500$g tooth paste sample has $0.02gm$ fluoride concentration. What is the concentration of fluorine in terms of ppm levels?

• A. $250$
• B. $40$
• C. $400$
• D. $1000$

Answer 1

Answer: (B)

$40$

Given,
$500$ $g$ tooth paste $\Rightarrow 0.02$ $gm$ flouride

$ppm\to$ Parts per million.

So, for a million gram toothpaste.

$500-0.02$

$1000000-\left(x\right)ppm$

$⟹500\times x=0.02\times 1000000$

$⟹x=\frac{200}{5}$

Flourine in ppm $=40$ ppm

Hence, the correct option is $C$