Answer:
K₂Cr₂O₇(s) ⇒ 2 K⁺(aq) + Cr₂O₇²⁻(aq)
Explanation:
Potassium dichromate (K₂Cr₂O₇) is a strong electrolyte, that is, when dissolved in water (the medium), it dissociates in cation potassium (K⁺) and anion dichromate (Cr₂O₇²⁻). The balanced dissociation equation is:
K₂Cr₂O₇(s) ⇒ 2 K⁺(aq) + Cr₂O₇²⁻(aq)
Given concentration of NaCl=15%
Means ,
In every 100g of Solution 15g of NaCl is present .
Now
So ,
<u>37.5g of NaCl present in 250g of solution.</u>
It should be B. All of the other choices are used often by abusers
To find moles in this sample, you would divide grams by molar mass of ethyl alcohol
(18.0g)/(46.07g/mol) = 0.391mol C2H6O
First find the oxidation states of the various atoms:
<span>in Cr2O2 2- Cr @ +1; In NH3 N @ +3; in CrO3 Cr @ +3, N2 N @ 0 </span>
<span>Note that N gained electrons, ie, was reduced; Cr was oxidized </span>
<span>Now there is a problem, because B has NH4+ which the problem did not, and is not balanced, showing e- in/out </span>
<span>B.NH4+ → N2 </span>
<span>Which of the following is an oxidation half-reaction? </span>
<span>A.Sn 2+ →Sn 4+ + 2e- </span>
<span>Sn lost electrons so it got oxidized</span>
