I’m pretty sure it would be B
Answer:
11.31g NaClO₂
Explanation:
<em> Is given 250mL of a 1.60M chlorous acid HClO2 solution. Ka is 1.110x10⁻². What mass of NaClO₂ should the student dissolve in the HClO2 solution to turn it into a buffer with pH =1.45? </em>
It is possible to answer this question using Henderson-Hasselbalch equation:
pH = pKa + log₁₀ [A⁻] / [HA]
<em>Where pKa is -log Ka = 1.9547; [A⁻] is the concentration of the conjugate base (NaClO₂), [HA] the concentration of the weak acid</em>
You can change the concentration of the substance if you write the moles of the substances:
[Moles HClO₂] = 250mL = 0.25L×(1.60mol /L) = <em>0.40 moles HClO₂</em>
Replacing in H-H expression, as the pH you want is 1.45:
1.45 = 1.9547 + log₁₀ [Moles NaClO₂] / [0.40 moles HClO₂]
-0.5047 = log₁₀ [Moles NaClO₂] / [0.40 moles HClO₂]
<em>0.3128 = </em>[Moles NaClO₂] / [0.40 moles HClO₂]
0.1251 = Moles NaClO₂
As molar mass of NaClO₂ is 90.44g/mol, mass of 0.1251 moles of NaClO₂ is:
0.1251 moles NaClO₂ ₓ (90.44g / mol) =
<h3>11.31g NaClO₂</h3>
Answer:
Barium precipitation : in this method we will add Barium chloride to the wastewater to precipitate Barium sulphate precipitate from the waste water
Explanation:
The measures that can be taken for the recovery of sulfates and other contaminants from wastewater includes : ion exchange, precipitation and Reverse osmosis. of all these measures i will discuss precipitation
Precipitation measures can be performed using different methodologies the methodology that i will discuss is :
Barium precipitation : in this method we will add Barium chloride to the wastewater to precipitate Barium sulphate precipitate from the waste water
The sulphate contained in the wastewater can be reduced to as low as 200 mg/l using this method
Temperature : the increase in temperature of the waste water will cause the reduction in formation of sulphate in the waste water
PH changes : for the precipitation of sulphate to be effective the required PH level is 4.5
Your independent variable is - The kind of nail polish used
Your dependent variable is - How much the nails have grown
And your constant is - Amount of time allowed for growth
The mass numbers for two isotopes are unequal because they have different numbers of NEUTRONS.
