Experiment title: diels-alder reaction. organic technique and overview: synthesis by a cycloaddition reaction involves 1,4-addition of conjugated dienes, in which 2 sigma bonds are formed from two pi bonds. goal of the experiment: synthesize cis-norbornene-5, 6-end-dicarboxylic anhydride from maleicanhydride and cyclopentadiene. experiment protocol: 1). dissolve 0.2g of maleic anhydride in 1.0ml ethyl acetate in a test tube. to this solution, add 1.0ml of hexanes (ligroin). a solvent mixture is used in this reaction because the product is too soluble in 100% ethyl acetate and would not precipitate. 2). add 0.2ml of cyclopentadiene and mix gently with a glass rod. observe the reaction. did the test tube heat up? 3). allow the tube to cool to room temperature, during which crystallization should occur. if it does not, induce it by scratching the inside of the tube with a glass stirring rod. if precipitation still does not occur, cool the solution in an ice bath 4). remove the solvent by vacuum filtration on a hirsch funnel. use a small amount of hexanes to wash the residual crystals from the test tube into the funnel. leave the crystals in the hirsch funnel for a few minutes, with the water still on, to dry them. 5). collect the crystals from the hirsch funnel--if they still seem wet, dry them by pressing them in a folded piece of large filter paper. determine the mass of the product and calculate the percent yield. 6). test the melting point of the final product.

answer : the correct answer is 2) hno₃ and naoh .

arrhenius concept of acid and base :

acid :

according to arrhenius acid are those which release h⁺ or hydronium ion (h₃o⁺) in aqueous solution .

example : hcl +h₂o ↔ h₃o⁺ + cl⁻

hcl is giving h₃o⁺ ion in water , hence it is an arrhenius acid .

base :

according to arrhenius , bases are those which releases oh⁻ ions in aqueous solution .

example : koh (aq) ↔ k⁺ + oh⁻

since koh is producing oh⁻ ions hence , it is an arrhenius base .

checking the options :

1) ch₃oh and naoh :

ch₃oh is known as methanol , an organic compound , which is neutral compound . the dissociation of ch₃oh is negligible . it is very very weak acid (ka = 3.2 * 10 ⁻¹² ) .

naoh being ionic gives na⁺ and oh⁻ ions in aqueous solution as :

naoh ↔ na⁺ + oh⁻ . hence it is an arrhenius base

it can be concluded that ch₃oh and naoh is not arrhenius acid and base.

2) hno₃ and naoh :

hno₃ is an ionic compound which gives ions h⁺ and no₃⁻ ion in aqueous solution as:

hno₃ + h₂o ↔ h₃o⁺ + no₃⁻

since it is giving h⁺ ion . hno₃ is arrhenius acid .

naoh being ionic gives na⁺ and oh⁻ ions in aqueous solution as :

naoh ↔ na⁺ + oh⁻

. hence it is an arrhenius base .

it can be said that hno₃ and naoh are arrhenius acid and base.

3) ch₃oh and hcl

as discussed ch₃oh is neutral compound .

while hcl in aqueous solution dissociates to give h⁺ and cl⁻ ions as :

hcl + h₂o→ h₃o⁺ + cl⁻ . so hcl is arrhenius acid .

hence , ch₃oh and hcl are not arrhenius acid and base.

4) hno₃ and hcl :

hno₃ as discussed gives h⁺ in aqueous solution , while hcl also gives h⁺ in aqueous solution .

hence both hno₃ and hcl are arrhenius acid they are not acid and base .

so the arrhenius acid and base are 2) hno₃ and naoh.