The Ka of a certain indicator is 4 ×10−7. The color of HIn is green and that of In− is red. A few drops of the indicator are added to an HCl solution, which is then titrated against an NaOH solution. Over which pH range will the indicator change color?4.4 to 6.46.4 to 8.43.4 to 5.47.4 to 9.45.4 to 7.4

pH range of indicator is 5.4 to 7.4

Explanation:

An acid-base indicator are chemical substances that change in color when pH changes.

An indicator changes in color when the pH of the solution is equal to pKa of the indicator (Where pKa is defined as - log Ka).

The pH range in which indicator changes in color is pKa ± 1.

pKa of buffer is:

- log 4x10⁻⁷ = 6.4

That means pH range of indicator is since 6.4 - 1 = 5.4 to 6.4 + 1 = 7.4.

(5.4 - 7.4)

answer: the enthalpy of the overall chemical reaction is +87.88 kj or +88 kj.

according to hess's law, the overall enthalpy of a reaction is the difference between the sum of enthalpy values of all the products and the sum of enthalpy values of all the reactants.

δh(reaction) = ∑nδh(products) - ∑nδh(reactants)

δh(reaction) = [δh +δh] - [δh]

δh(reaction) = [1(-287.02) + 1(0) ] - [1(-374.9)] kj = +87.88 kj

here, δh (pcl3) = -287.02 kj, δh(cl2) = 0, δh(pcl5) = -374.9 kj

therefore, enthalpy of the overall reaction is +87.88 kj or +88 kj.

there are no statements provided but here is why:

sulfur belongs to group 16 because it can be found in nature whether it is in a free or combined state.

hope this