How can the following compounds be prepared using ethyne as the starting material?

Acetal dehyde can be prepared using ethyne as the starting material and by using H₂O, H₂SO₄, HgSO₄ as reagents.

Propan-2-one can be prepared using ethyne as the starting material and by using NaNH₂, CH₃CH₂Br and H₂/Lindlar catalyst as reagents.

1,2-dibromobutane can be prepared using ethyne as the starting material and by using NaNH₂, CH₃Br and H₂O, H₂SO₄, HgSO₄ as reagents.

(E) Pent -2-ene can be prepared using ethyne as the starting material and by using NaNH₂, CH₃Br and Na, NH₃ (liq) as reagents

(Z) Pent-2-ene can be prepared using ethyne as the starting material and by using NaNH₂, CH₃Br and NaNH₂, CH₃CH₂Br as reagents.

Pentane can be prepared using ethyne as the starting material and by using NaNH₂, CH₃Br and excess H₂, Pd/C as reagents.