Which of the following reactions as written

corresponds to a standard formation reaction?
1. 2H (g) + O2(g) ! H2O2 (`)
2. Na(s) +
1
2
Cl2(g) ! NaCl(s)
3. CO2(s) ! CO2(g)
4. SO2(g) +
1
2
O2(g) ! SO3(g)
5. 2 H2(g) + O2(g) ! 2 H2O(`)

1. 2H(g)+O2(g)->H2O2

2. Na(s)+1/2Cl2->NaCl(s)
3. Co2(s)->Co2(g)
4. So2(g)+1/2O2->So3(g)
5. 2H2(g)+O2(g)->2H2O

1 is not.

2 is if you have 1/2 Cl2(g)
3. I don't understand the 2 but I think this is not because for Co I would write Co and not Co2.
4 is if you write 1/2 O2(g)
5 is not. You can make it one by
H2(g) + 1/2 O2(g) ==> H2O(g)

1. None of them. They're all too serious to be considered standard formation reactions. Maybe they should loosen up and tell a few jokes to lighten the atmosphere.

A standard formation reaction is a reaction in which one mole of a compound is formed from its constituent elements in their standard states. The reaction with the correct standard formation reaction is:

2 H2(g) + O2(g) → 2 H2O(`) (Option 5)

In this reaction, two moles of H2 gas react with one mole of O2 gas to form two moles of H2O in its standard state.

The other reactions listed are not standard formation reactions.

In order to determine which of the reactions corresponds to a standard formation reaction, we need to understand what a standard formation reaction is.

A standard formation reaction is a chemical reaction that forms one mole of a compound from its constituent elements in their standard state at a given temperature and pressure. The standard state of a substance is the most stable form of the substance under standard conditions, which is usually defined as a pressure of 1 atmosphere and a temperature of 25 degrees Celsius.

To identify a standard formation reaction, we need to check if the reaction equation represents the formation of one mole of a compound from its constituent elements in their standard state.

Let's analyze each of the provided reactions:

1. 2H (g) + O2(g) → H2O2 (`)
This reaction does not correspond to a standard formation reaction because it forms hydrogen peroxide (H2O2) instead of water (H2O), and hydrogen peroxide is not in its standard state.

2. Na(s) + 1/2 Cl2(g) → NaCl(s)
This reaction corresponds to a standard formation reaction because it forms one mole of sodium chloride (NaCl) from its constituent elements (sodium and chlorine) in their standard states.

3. CO2(s) → CO2(g)
This reaction does not correspond to a standard formation reaction because it does not form a compound from its constituent elements.

4. SO2(g) + 1/2 O2(g) → SO3(g)
This reaction does not correspond to a standard formation reaction because it forms sulfur trioxide (SO3) instead of sulfur dioxide (SO2), and sulfur trioxide is not in its standard state.

5. 2 H2(g) + O2(g) → 2 H2O(`)
This reaction does not correspond to a standard formation reaction because it forms water in a non-standard state (`) instead of its standard state (liquid).

Based on the analysis, the only reaction that corresponds to a standard formation reaction is:

2. Na(s) + 1/2 Cl2(g) → NaCl(s)