Write the formula of the compound formed by `K_(2)Cr_(2)O_(7)` in alkaline solution with `30% H_(2)O_(2)`:

Answer

To determine the formula of the compound formed by potassium dichromate (K₂Cr₂O₇) in alkaline solution with 30% hydrogen peroxide (H₂O₂), we can follow these steps:

### Step 1: Identify the Reactants
The reactants in this reaction are potassium dichromate (K₂Cr₂O₇) and hydrogen peroxide (H₂O₂) in an alkaline medium. We can use potassium hydroxide (KOH) as the alkaline solution.

### Step 2: Write the Reaction
When potassium dichromate reacts with hydrogen peroxide in an alkaline solution, the reaction can be represented as follows:

\[ K_2Cr_2O_7 + H_2O_2 + KOH \rightarrow K_3CrO_8 + H_2O \]

### Step 3: Balance the Reaction
To balance the reaction, we need to ensure that the number of atoms of each element is the same on both sides. The balanced equation is:

\[ 2 K_2Cr_2O_7 + 7 H_2O_2 + 4 KOH \rightarrow 2 K_3CrO_8 + 9 H_2O \]

### Step 4: Identify the Product
From the balanced equation, we see that the product formed is potassium chromate with the formula K₃CrO₈.

### Step 5: Determine the Oxidation State
In K₃CrO₈, the chromium is in the +5 oxidation state due to the presence of peroxide linkages.

### Final Answer
The formula of the compound formed by K₂Cr₂O₇ in alkaline solution with 30% H₂O₂ is:

\[ K_3CrO_8 \]

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