Answer:
Hydrogen
Explanation:
Hydrogen can never be central atom despite its low electronegativity
Answer:because it isnt flammable
Explanation:water can not be burned
18. Reaction will occur.
19. Reaction Will occur.
20. Reaction will occur.
21. Reaction will occur.
22. Reaction won't occur.
23. Reaction will occur.
24. Reaction will occur.
25. Reaction won't occur.
<h3><u>Explanation</u>:</h3>
The reaction rate of the metals with water, steam, acid, or hydroxides or their inert behavior towards them are noted in the metal activity series.
It contains all the metals one after the other which and the upper metal can replace the lower metal from its salt.
Calcium can replace hydrogen from acid, so the reaction will occur in 18. The products formed are calcium phosphate and hydrogen gas.
Chlorine is more reactive than bromine. So it can replace bromine from its salt to from bromine gas and magnesium chloride.
Aluminium can replace iron from its salt. So it will form aluminium oxide and iron metal. This reaction is used to obtain iron from ores.
Zinc can replace hydrogen from acid. So the products will be zinc chloride and hydrogen gas.
Chromium cannot displace hydrogen form water. So the reaction won't occur.
Tin can replace hydrogen form acid. So the reaction will proceed.
Magnesium will replace platinum from its salt. So magnesium oxide and platinum will form.
Bismuth cannot replace hydrogen from acid. So the reaction won't proceed.
Answer:
Change the temperature and pressure
Explanation:
In case we are analyzing the solubility of a salt in some solvent, raising the temperature would increase the solubility of a salt generally. In contrast, at lower temperatures the solubility of ionic salts would decrease.
Now, another variation of this scenario might be solubility of gases. According to Henry's Law, 
, meaning that the solubility of a gas is directly proportional to its partial pressure. Therefore, the greater the pressure, the greater the solubility of a gas.
Answer:
Chemical formula of Oxygen is O2.
We know ,
1 mole of a substance contains 6.022×10^23, Avogadro’s Constat.
Here, Molar mass of O = 16u
And molar mass of O2 = 32u
And 32g of O2 = 1 mole of O2
It means that,
32g of O2 = 6.022×10^23 molecules
