C is the correct answer. Double displacement reaction, also called as metathesis, is a type of reaction wherein two compounds react to form new compounds. This case the cations and the anions of the reactants replace each other forming the new compounds.
Answer: There are 7 alpha-particle emissions and 4 beta-particle emissions involved in this series
Explanation:
Alpha Decay: In this process, a heavier nuclei decays into lighter nuclei by releasing alpha particle. The mass number is reduced by 4 units and atomic number is reduced by 2 units.
Beta Decay : It is a type of decay process, in which a proton gets converted to neutron and an electron. This is also known as -decay. In this the mass number remains same but the atomic number is increased by 1.
In radioactive decay the sum of atomic number or mass number of reactants must be equal to the sum of atomic number or mass number of products .

Thus for mass number : 235 = 207+4X
4X= 28
X = 7
Thus for atomic number : 92 = 82+2X-Y
2X- Y = 10
2(7) - Y= 10
14-10 = Y
Y= 4

Thus there are 7 alpha-particle emissions and 4 beta-particle emissions involved in this series
Answer:
K = [ HOCl ] . [HgO. HgCl2] / [Cl2]^2 [H2O] [HgO]^2
Explanation:
The law of Mass Action states that, at constant temperature, the rate of reaction is proportional to the active masses of each of the reactants.
The reaction above is a reversible reaction and the law of mass action also applies to it.
The rate of reaction from left-to-right reaction = r1 = k. [Cl2]^2 [H2O] [HgO]^2
Rate of reaction from right - to - left r2 = k. [hocl]^2 [HgO . hgcl2]
Then at equilibrium,
r1 = r2
k1/k2 = [HOCl ]^2 [HgO. HgCl2] / [Cl2]^2 [H2O] [HgO]^2 = K
where K is the equilibrium constant for the reaction.
Density can be calculated using the following rule:
density=mass/volume
therefore,
volume=mass/density
we have mass=0.451g and density=0.824g/ml
substituting in the above equation, we can calculate the volume as follows:
volume = 0.451/0.824 = 0.547 ml