Which of the following oxides will be the least acidic?

Options

A. `As_(4)O_(6)`
B. `As_(4)O_(10)`
C. `P_(4)O_(10)`
D. `P_(4)O_(6)`

Explanation

To determine which of the given oxides is the least acidic, we will follow these steps:

### Step 1: Identify the Oxides
First, we need to identify the oxides provided in the question. The oxides mentioned are likely from the elements arsenic (As) and phosphorus (P), which belong to group 15 of the periodic table.

### Step 2: Understand Acidic Character in Group 15
In group 15, as we move down the group from nitrogen to phosphorus to arsenic, the acidic character of their oxides decreases while the basic character increases. This trend occurs due to the decrease in electronegativity and the ability of the nucleus to attract electrons as we move down the group.

**Hint:** Remember that acidic character decreases down the group, while basic character increases.

### Step 3: Compare the Oxides
Next, we need to compare the specific oxides mentioned, which are likely P4O10, P4O6, As4O10, and As4O6. According to the trend, we can already infer that oxides of phosphorus (P) will be more acidic than those of arsenic (As).

**Hint:** Compare the elements in the same group; the higher the element in the group, the more acidic its oxides.

### Step 4: Determine Oxidation States
Now, we will calculate the oxidation states of arsenic in As4O6 and As4O10 to further compare their acidic character.

- For As4O6:
- Let the oxidation state of As be x.
- The equation will be: 4x + 6(-2) = 0
- Solving gives: 4x - 12 = 0 → x = +3

- For As4O10:
- The equation will be: 4x + 10(-2) = 0
- Solving gives: 4x - 20 = 0 → x = +5

**Hint:** The higher the oxidation state, the more acidic the oxide tends to be.

### Step 5: Compare Acidic Character Based on Oxidation States
From the calculations:
- As4O6 has an oxidation state of +3.
- As4O10 has an oxidation state of +5.

Since As4O10 has a higher oxidation state, it will be more acidic than As4O6.

**Hint:** Higher oxidation states correlate with higher acidity.

### Step 6: Conclusion
Based on the trends and calculations:
- P4O10 and P4O6 are more acidic than both As4O6 and As4O10.
- Between As4O6 and As4O10, As4O6 is the least acidic.

Thus, the least acidic oxide among the given options is **As4O6**.

**Final Answer:** As4O6