Answer:
[HF]₀ = 0.125M
Explanation:
NaOH + HF => NaF + H₂O
Adding 20ml of 0.200M NaOH into 25ml of HF solution neutralizes 0.004 mole of HF leaving 0.004 mole NaF in 0.045L with 0.001M H⁺ at pH = 3. This is 0.089M NaF and 0.001M HF remaining.
=> 45ml of solution with pH = 3 and contains 0.089M NaF from titration becomes a common ion problem.
HF ⇄ H⁺ + F⁻
C(eq) [HF] 10⁻³M 0.089M (<= soln after adding 20ml 0.200M NaOH)
Ka = [H⁺][F⁻]/[HF]₀ => [HF]₀ = [H⁺][F⁻]/Ka
[HF]₀ = (0.001)(0.089)/(7.1 x 10⁻⁴) M = 0.125M
Can you type it out the picture is too blurry to read, sorry.
Answer:
detail is given below.
Explanation:
This law was given by French chemist Antoine Lavoisier in 1789. According to this law mass of reactant and mass of product must be equal, because masses are not created or destroyed in a chemical reaction.
Law of conservation of mass:
According to the law of conservation mass, mass can neither be created nor destroyed in a chemical equation.
For example:
In given photosynthesis reaction:
6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂
The given equation is balanced chemical equation of photosynthesis. There are six carbon atoms, eighteen oxygen atoms and twelve hydrogen atoms on the both side of equation so this reaction followed the law of conservation of mass.
If equation is not balanced,
CO₂ + H₂O → C₆H₁₂O₆ + O₂
It can not follow the law of conservation of mass because mass is not equal on both side of equation.
Phenolphthalein<span> is often used as an indicator in acid–base titrations. For this application, it </span>turns<span> colorless in acidic solutions and </span>pink<span> in basic solutions. </span>Phenolphthalein<span> is slightly soluble in water and usually is dissolved in alcohols for use in experiments.
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