4HBr(aq) + O2(g)= 2H2O(l) + 2Br2(l)
Answer:
b. Extraction with a solution of sodium hydrogen carbonate, separating the layers, followed by drying and evaporating the organic layer.
Step-by-step explanation:
The ether solution contains your product, benzaldehyde, and some starting material, benzoic acid, the purification steps are:
- Extract with a solution of NaHCO₃. The ether layer contains benzaldehyde, and the aqueous layer contains sodium benzoate.
- Separate the layers. Keep the ether layer.
- Dry the ether solution.
- Distill the ether (boiling point 35 °C) and purify the benzaldehyde (178 °C) by steam distillation.
a. is wrong. Extraction with HCl will not remove much of the benzoic acid.
c. is wrong. If you evaporate the organic layer, you will have a mixture of benzaldehyde and benzoic acid.
d. is wrong. If you work with the aqueous layer, you will end up with benzoic acid,
Physical changes occur when objects or substances undergo a change that does not change their chemical composition. This contrasts with the concept of chemical change in which the composition of a substance changes or one or more substances combine or break up to form new substances.
Answer:
0.0164 g
Explanation:
Let's consider the reduction of silver (I) to silver that occurs in the cathode during the electroplating.
Ag⁺(aq) + 1 e⁻ → Ag(s)
We can establish the following relations.
- 1 A = 1 C/s
- The charge of 1 mole of electrons is 96,468 C (Faraday's constant)
- 1 mole of Ag(s) is deposited when 1 mole of electrons circulate.
- The molar mass of silver is 107.87 g/mol
The mass of silver deposited when a current of 0.770 A circulates during 19.0 seconds is:
