Answer:
The correct option is: b. pH 6.4-8.0
Explanation:
Phenol red is a weak acid that is used as a pH indicator and exists in the form of stable red crystals.
<u>The color of the phenol red solution changes from yellow to red when the change in pH is observed. The color of phenol red transitions from yellow to red when the pH is 6.8 - 8.2 or 6.4 - 8.0</u>
Above the pH of 8.2, the phenol red solution turns a bright pink in color.
Answer:
the concentration of 
in the original solution= 0.0088 M
the concentration of 
in the original solution = 0.058 M
Explanation:
Given that:
The volume of the sample containing Cd2+ and Mn2+ = 50.0 mL; &
was treated with 64.0 mL of 0.0600 M EDTA
Titration of the excess unreacted EDTA required 16.1 mL of 0.0310 M Ca2+
i.e the strength of the Ca2+ = 0.0310 M
Titration of the newly freed EDTA required 14.2 mL of 0.0310 M Ca2+
To determine the concentrations of Cd2+ and Mn2+ in the original solution; we have the following :
Volume of newly freed EDTA = 
= 
= 7.3367 mL
concentration of = 
= 
= 0.0088 M
Thus the concentration of in the original solution = 0.0088 M
Volume of excess unreacted EDTA = 
= 
= 8.318 mL
Volume of EDTA required for sample containing and = (64.0 - 8.318) mL
= 55.682 mL
Volume of EDTA required for = Volume of EDTA required for
sample containing and
-- Volume of newly freed EDTA
Volume of EDTA required for = 55.682 - 7.3367
= 48.3453 mL
Concentration of = 
Concentration of = 
Concentration of in the original solution= 0.058 M
Thus the concentration of = 0.058 M
Let's think, if you have a candle ( that is not blown out ) the physical properties are the candles mass and hence ( hence of the candle is the stiffness of the candle), weight, length, density, surface friction ( force resisting the relative motion of solid surface), and the energy content. You then, need to go to bed, so, therefore, you want to blow the candle out. Once you blow the candle out, the candle is evidently going to have at least a couple of different physical properties, than before it was blown out. The physical properties are a different color, the length of the candle, the texture, you could also apply the mass of the candleholder, and then, the mass of the candleholder and the candle, last but not least, the mass of just the candle. Once you observe the candle, you should be able to plug in those observations into the physical properties. As to, because you asked' what are the physical properties of a candle that has been blown out... We are going to assume that we did observe the candle, and the length of the candle in cm, after being blown out is 30cm. (12 inches; customary). Next, that the color of the candle is the same (let us say the original color is taffy pink). We can then say that the texture of the candle is waxy and the top and smooth as you get to the bottom ( the texture depends on how long the candle was burning, but we are saying that we lit the candle, and then immediately blew the flame out ) . We now have the mass of the candleholder, which will scientificity stay the same. Now, for the mass of the candleholder and the candle, that all depends of how long you let it burn ( remember, we are saying we lit the wick and then immediately blew the fame out ). So, the candle really didn't change is mass, so, therefore, wouldn't affect the mass of the candleholder including the candle. That also goes to the mass of the candle.
