Answer: (a) K *[A][B]^2
(b) The answer is B
Explanation:
A)
Step1:A+B<--> C (fast)
Step2: B+C→D(slow)
Rate depends on slowest step.
so,
rate = k' [B][C] ...eqn 1
But C is intermediate.so use step 1
Since 1st step is an equilibrium,
Kc = [C] /[A][B]
so,
[C] = Kc [A][B] ...eqn 2
put eqn 2 in eqn 1
rate = k' *[B] * Kc [A][B]
= k'Kc*[A][B]^2
= K *[A][B]^2 {writing k'Kc = K}
Answer: K *[A][B]^2
B)
Answer is B
Since rate depends on slowest step.
if slowest step is:
X2Y2+Z2→X2Y2Z+Z
then only,
rate= k[X2Y2][Z2]
Answer: B
Answer:
The proportion of dissolved substances in seawater is usually expressed in ppm, ppb or ppt
Explanation:
The concentration of very diluted solutions should be expressed in parts per million, billion or trillion.
ppm = mass from the solute . 10⁶ / mass or volume of the solution
ppb = mass from the solute . 10⁹ / mass or volume of the solution
ppt = mass from the solute . 10¹² / mass or volume of the solution
ppm = mg/kg, μg/g, μg/mL → These are the units
ppb = ng/g
ppt = pg/g
Answer: 
Explanation: A double displacement reaction is one in which exchange of ions take place.
The compounds which are soluble in water are designated by symbol (aq) and those which are insoluble in water and remain in solid form are represented by (s) after their chemical formulas.
Thus the exchange of ions take place and all the compounds are soluble so the chemical formulas are followed by the symbol (aq).
