Consider the following ionic compounds: CdCO3, Na2S, PbSO4, (NH4)3PO4, and Hg2Cl2. Which compounds will be soluble when added to water? a. Na2S and (NH4)3PO4
b. Hg2Cl2
c. Hg2Cl2, Na2S, and (NH4)3PO4
d. CdCO3, PbSO4, and Hg2Cl2

a. Na₂S and (NH₄)₃PO₄ .

Explanation:

To know which salts are soluble we need to remember some solubility rules. And apply these as follows:

* All compounds of group 1 (Li⁺, Na⁺, K⁺, etc.) are soluble, Na₂S is soluble.

* All ammonium salts are soluble,

* All Cl⁻, I⁻, Br⁻ are soluble except when are with Ag⁺, Hg₂²⁺, Pb²⁺, Hg₂Cl₂ is insoluble

* Carbonates are insoluble except those with group 1 or ammonium, CdCO₃ is insoluble

* All sulfates are soluble except those with Ca²⁺, Sr²⁺, Ba²⁺, Pb²⁺, Ag⁺. PbSO₄ is insoluble.

Right solution is:

answer is: nuclear fusion produces elements that are heavier than helium.

nuclei combine to form a heavier nucleus, releasing energy.  

for example, fusion of hydrogen atoms at the sun.  

this fusion nuclear reaction is in the inner core of the sun and hydrogen (atomic number 1) is conveted into helium (atomic number 2).  

the inner core is the central region of the sun and all solar energy is produced in the core by nuclear fusion.