Answer:
D. They react readily with oxygen in the air
D. Metals
Elements that are shiny, solid, conducts electricity, has atomic mass of 108 is metal.
Answer:
pH = 4.26
Explanation:
Bromocresol green is a commonly used pH indicator. The concentration ratio of the acid form to base form explains its color, which reflects the pH of the medium.
C₂₁H₁₄Br₄O₅S + H₂O ⇄ C₂₁H₁₃Br₄O₅S⁻ + H₃O⁺
acid conjugate base
We can calculate the pH through Henderson-Hasselbalch's equation:
![pH=pKa+log(\frac{[base]}{[acid]} )=4.66+log(\frac{1}{2.49} )=4.26](https://tex.z-dn.net/?f=pH%3DpKa%2Blog%28%5Cfrac%7B%5Bbase%5D%7D%7B%5Bacid%5D%7D%20%29%3D4.66%2Blog%28%5Cfrac%7B1%7D%7B2.49%7D%20%29%3D4.26)
Volume Ba(OH)2 = 23.4 mL in liters :
23.4 / 1000 => 0.0234 L
Molarity Ba(OH)2 = 0.65 M
Volume HNO3 = 42.5 mL in liters:
42.5 / 1000 => 0.0425 L
number of moles Ba(OH)2 :
n = M x V
n = 0.65 x 0.0234
n = 0.01521 moles of Ba(OH)2
Mole ratio :
<span>Ba(OH)2 + 2 HNO3 = Ba(NO3)2 + 2 H2O
</span>
1 mole Ba(OH)2 ---------------- 2 moles HNO3
0.01521 moles ----------------- moles HNO3
moles HNO3 = 0.01521 x 2 / 1
moles HNO3 = 0.03042 / 1
= 0.03042 moles HNO3
Therefore:
M ( HNO3 ) = n / volume ( HNO3 )
M ( HNO3 ) = 0.03042 / 0.0425
M ( HNO3 ) = 0.715 M
