<span>Ultra violet light is the catalyst that converts 7-dehydrocholesterol to provitamin D3. Ultra violet light can be obtained from the sun. The conversion happens when UVB light hits the skin (where 7-dehydrocholesterol naturally resides), gets absorbed, and us metabolized inside of the body.</span>
Answer: 1 × 10−2 M
Explanation: Kw is known as the constant of water dissociation and its value is found to be
. It is the product of the concentration of [H3O+] and [OH -] ions .
Dissociation of water can be represented by -

Kw = [H3O+] [OH -]
As we know that pKw = - log Kw,
Thus pKw = 14
pOH = - log OH- = - log (10^{-12}) = 12
and pKw = pH + pOH
14 = pH + 12
pH = 14 - 12 = 2
pH = -log H3O+
2 = -log H3O+
Therefore, [H3O+] = 1 × 10−2 M
That would be the element aluminum.
Natural, Organic & Manmade Fibers. after flame is out there is a soft gray ash!