A double replacement reaction occurs when the ionic parts of two ionic compounds are exchanged.
Reaction 1 results in a product which is a single compound. No ionic parts are exchanged.
Reaction 3 results in one compound being separated into its elemental parts. No ionic parts are exchanged.
Reaction 4 has two reactants, but Pb is an element and not an ionic compound. No ionic parts are exchanged.
Hence, the answer is Reaction 2. Both NaBr and Ca(OH)2 are ionic compounds. Br - is the anion in NaBr, and (OH)2 is also an anion. Ionic parts are exchanged.
Answer:
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Step-by-step explanation:
Answer:
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Step-by-step explanation:
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The constant should be added to form a perfect square trinomial will be 1/4. Then the correct option is D.
<h3>What is a quadratic equation?</h3>
It's a polynomial with a value of zero. There exist polynomials of variable power 2, 1, and 0 terms. A quadratic equation is an equation with one statement in which the degree of the parameter is a maximum of 2.
The expression is x² + x.
Then the constant should be added to form a perfect square trinomial.
Then the constant will be
The square of the half of the coefficient of the variable x is to be added to make a perfect square.
Then the constant will be 1/4.
Then the perfect square will be

More about the quadratic equation link is given below.
brainly.com/question/2263981
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