Step 1:

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The concentration of $\"\"$ M.

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The nitrous solution ionization constant $\"\"$ .

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The nitrous acid is a weak acid and $\"\"$ is strong base.

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$\"\"$

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$\"\"$ .

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Acid ionization constant for above reaction is

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$\"\"$ .

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The concentration of $\"\"$ at the equivalence point. \ \ Substitute $\"\"$ M.

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$\"\"$ .

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Substitute $\"\"$ .

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$\"\"$

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$\"\"$

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$\"\"$

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$\"\"$

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$\"\"$ .

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$\"\"$

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$\"\"$ .

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$\"\"$

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Substitute $\"\"$ .

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$\"\"$

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The $\"\"$ at the equivalence point is $\"\"$ .

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Solution:

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The $\"\"$ at the equivalence point is $\"\"$ .