The compounds that form a clear homogeneous solution on treatment with cold dilute sulfuric acid (H2SO4) are as follows:

1. 1-Propyne: It is an alkyne compound with the chemical formula C3H4. When treated with cold dilute H2SO4, it undergoes an addition reaction to form 2,3-dibromobutane. This reaction occurs via the Markovnikov addition of water across the triple bond.

2. Pyridine: It is a heterocyclic aromatic compound with the chemical formula C5H5N. Pyridine does not undergo any reaction with cold dilute H2SO4 and remains unchanged. It is a weak base and does not react with acids.

3. Ethyl butanoate: It is an ester compound with the chemical formula C6H12O2. When treated with cold dilute H2SO4, esters undergo hydrolysis to form the corresponding alcohol and carboxylic acid. In the case of ethyl butanoate, it will hydrolyze to form butan-1-ol and butanoic acid.

4. THF (Tetrahydrofuran): It is a cyclic ether compound with the chemical formula C4H8O. THF does not undergo any reaction with cold dilute H2SO4 and remains unchanged. It is a stable compound and does not react with acids under normal conditions.

5. Propoxypropane: It is an ether compound with the chemical formula C6H14O. Similar to THF, propoxypropane does not react with cold dilute H2SO4 and remains unchanged. Ethers are generally unreactive towards acids.

6. Propan-1-amine: It is an amine compound with the chemical formula C3H9N. When treated with cold dilute H2SO4, amines can undergo protonation to form their corresponding ammonium salts. In the case of propan-1-amine, it will form propan-1-ammonium sulfate.

7. Propane: It is a saturated hydrocarbon with the chemical formula C3H8. Propane does not undergo any reaction with cold dilute H2SO4 and remains unchanged. Hydrocarbons are generally unreactive towards acids.

8. Cyclohexane: It is a cyclic hydrocarbon with the chemical formula C6H12. Cyclohexane does not undergo any reaction with cold dilute H2SO4 and remains unchanged. Hydrocarbons are generally unreactive towards acids.

9. Cyclohexanone: It is a ketone compound with the chemical formula C6H10O. Ketones do not undergo any reaction with cold dilute H2SO4 and remain unchanged. They are generally unreactive towards acids.

In conclusion, out of the given compounds, the ones that form a clear homogeneous solution on treatment with cold dilute H2SO4 are 1-Propyne, Propan-1-amine, Ethyl butanoate, and Cyclohexane.