Question

g A 0.25 mol sample of HBr is added to a 1.00 L buffer solution consisting of 0.68 M HCN and 0.35 M NaCN. Identify all species that exist in solution after the chemical reaction.

Answer 1

After the reaction between HBr and NaCN in the buffer solution, the species present will include HCN, excess HBr, NaBr, and any unreacted HCN from the original buffer.

Step-by-step explanation:

The student has added a 0.25 mol sample of HBr to a buffer solution containing 0.68 M HCN and 0.35 M NaCN. After this addition, the species that will exist in the solution are the result of the reaction between HBr and the NaCN, because HBr is a strong acid and will react with the base component of the buffer (NaCN) first before affecting the pH significantly.

The reaction can be represented by the following equation:
HBr + NaCN → NaBr + HCN

Since there is less moles of NaCN than HBr, the NaCN is the limiting reactant and will be completely consumed. The resulting species in the final solution will, therefore, include HCN, excess HBr, the newly formed NaBr, and any unreacted HCN from the original buffer.

Answer 2

See explaination for details and diagram

Step-by-step explanation:

We can say that Chemical reaction is a process in which one or more substances, the reactants, are converted to one or more different substances, the products. Substances are either chemical elements or compounds.

A chemical reaction rearranges the constituent atoms of the reactants to create different substances as products.

See attachment for the buffer of the chemical reaction.