Answer: C
Explanation:
According to Neils Bohr, atoms contain electrons which are arranged in energy levels. The energy levels proceed from the lowest to the highest. When energy is supplied to an atom,it moves from lower to higher energy levels. The higher energy level is known as the excited state. Excited states are short lived and atoms quickly return to ground state with emission of the absorbed energy in the form of visible light. This visible light must have one of the seven colours observed in the visible spectrum; Red, orange, yellow, indigo, blue, green, violet. Energy required for this excitation is supplied by heating the substance in a flame.
The question is incomplete, complete question is :
Determine the pH of an HF solution of each of the following concentrations. In which cases can you not make the simplifying assumption that x is small? ( for HF is .)
[HF] = 0.280 M
Express your answer to two decimal places.
Answer:
The pH of an 0.280 M HF solution is 1.87.
Explanation:3
Initial concentration if HF = c = 0.280 M
Dissociation constant of the HF =
Initially
c 0 0
At equilibrium :
(c-x) x x
The expression of disassociation constant is given as:
Solving for x, we get:
x = 0.01346 M
So, the concentration of hydrogen ion at equilibrium is :
The pH of the solution is ;
The pH of an 0.280 M HF solution is 1.87.