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能正确表示下列反应的离子方程式是 A. $\left(\mathrm{NH}_{4}\right)_{2} \mathrm{Fe}\left(\mathrm{...

Mar 19, 2024

能正确表示下列反应的离子方程式是 A.

\left(\mathrm{NH}_{4}\right)_{2} \mathrm{Fe}\left(\mathrm{SO}_{4}\right)_{2}

溶液与少量

\mathrm{Ba}(\mathrm{OH})_{2}

溶液反应:

\mathrm{SO}_{4}^{2-}+\mathrm{Ba}^{2+}=\mathrm{BaSO}_{4} \downarrow

B. 通电电解

\mathrm{MgCl}_{2}

水溶液:

2 \mathrm{Cl}^{-}+2 \mathrm{H}_{2} \mathrm{O} \quad 2 \mathrm{OH}^{-}+\mathrm{Cl}_{2} \uparrow+\mathrm{H}_{2} \uparrow

C. 乙酸乙酯与

\mathrm{NaOH}

溶液共热:

\mathrm{CH}_{3} \mathrm{COOCH}_{2} \mathrm{CH}_{3}+\mathrm{OH}^{-} \rightarrow \Delta \mathrm{CH}_{3} \mathrm{COO}^{-}+\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{OH}

\mathrm{CuSO}_{4}

溶液中滴加稀氨水:

\mathrm{Cu}^{2+}+2 \mathrm{OH}^{-}=\mathrm{Cu}(\mathrm{OH})_{2} \downarrow

Key Concept

Precipitation reaction

Explanation

When solutions of

\left(\mathrm{NH}_{4}\right)_{2}\mathrm{Fe}\left(\mathrm{SO}_{4}\right)_{2}

and

\mathrm{Ba}(\mathrm{OH})_{2}

are mixed,

\mathrm{BaSO}_{4}

precipitates due to the low solubility of barium sulfate in water.

Key Concept

Electrolysis of aqueous solutions

Explanation

During the electrolysis of

\mathrm{MgCl}_{2}

solution, chloride ions are oxidized at the anode to form chlorine gas, and water is reduced at the cathode to form hydroxide ions and hydrogen gas.

Key Concept

Saponification reaction

Explanation

Ethyl acetate (

\mathrm{CH}_{3}\mathrm{COOCH}_{2}\mathrm{CH}_{3}

) reacts with

\mathrm{NaOH}

to produce sodium acetate (

\mathrm{CH}_{3}\mathrm{COO}^{-}

) and ethanol (

\mathrm{CH}_{3}\mathrm{CH}_{2}\mathrm{OH}

) in a saponification reaction.

Key Concept

Formation of a metal hydroxide precipitate

Explanation

When dilute ammonia is added to a

\mathrm{CuSO}_{4}

solution, a blue precipitate of

\mathrm{Cu}(\mathrm{OH})_{2}

forms due to the reaction of

\mathrm{Cu}^{2+}

ions with

\mathrm{OH}^{-}

ions.