Answer is: a) in the presence of a base.
Phenolphthalein is colorless in acidic solutions and pink in basic solutions.
Acid-base indicators are usually weak acids or bases and they are chemical detectors for hydrogen or hydronium cations.
Example for acid-base indicator is phenolphthalein (molecular formula C₂₀H₁₄O₄).
When solution turns phenolphthalein pink, it means it is basic (pH>7).
First, we calculate of the concentration of the H+ ions in the solution from the pH given. Then, calculate the new concentration after dilution. Calculation are as follows:
pH = -log[H+]
5 = -log[H+]
[H+] = 1 x 10^-5 M
M1V1 = M2V2
<span>1 x 10^-5 M (V1) = M2(100V1)
</span>M2 = 1 x 10^-7
pH = -log[<span>1 x 10^-7</span>]
pH = 7
Elements are a one of a class of substances that cannot be seperwted into simpler substances by chemicalk means.
Compounds is a substance formed when two or more chemical elements are chemically bonded together.
Relation: When two elements or more are formed chemically together its called a compound without elements there won't be compounds and without compounds there won't be elements.
The answer is b. 4.2 mole. The balanced reaction formula is 2LiOH + H2SO4 -->Li2SO4 + 2H2O. And the ratio of mole number of the reactants is the same as the ratio of coefficients.
Actually, the ionic equation for this is a reversible
equation since codeine is a weak base. Any weak base or weak acids do not
completely dissociate which makes them a reversible process. The ionic equation
for this case is:
<span>C18H21O3N + H3O+ </span><=>
C18H21O3NH+ + H2O
