Answer to this question is C. Regarding the volume.
Answer: a. two substances present; two phases present : Heterogeneous mixture
b. two substances present; one phase present
: Homogeneous mixture
c. one substance present; one phase present
: pure substance.
d. one substance present; two phases present: Heterogeneous mixture
Explanation:
A pure substance is a substance which contains definite composition of only one type of component. Hence, it cannot be separated by physical means.
Mixture is a substance which contains two or more than two types of components and they can be separated by physical means as well.
Homogeneous mixtures: It is a mixture that has uniform composition throughout the solution and the particle size or shapes are not different. There is no physical boundary between the dispersed phase and dispersion medium.
Heterogeneous mixtures: It is a mixture that has non-uniform composition throughout the solution and the particle size or shapes are also different. There is a physical boundary between the dispersed phase and dispersion medium.
Explanation:
The relation between 
is given by :
Where :
= Ionic prodcut of water
The value of the first ionization constant of sodium sulfite = 
The value of 
:
The value of the second ionization constant of sodium sulfite = 
The value of 
:
Answer:
Selenium
Explanation:
Oxygen is present in the group sixteen.
This group consist of oxygen, sulfur, selenium, tellurium and polonium.
All of these have same number of valance electrons thus they show similar properties.
From the given list of elements only selenium is belong to oxygen family thus it has properties similar to the oxygen.
Electronic configuration of oxygen:
O = [He] 2s² 2p⁴
Electronic configuration of selenium:
Se = [Ar] 3d¹⁰ 4s² 4p⁴
While aluminium, boron and phosphorus are belongs to other groups that's why their properties are not similar to the phosphorus.
phosphorus is present in group 15.
Boron and aluminium are present in group 13.
3. There are more oxygen atoms on the reactant side than the product side
