Question

The correct formula of borax is Na\(_2\)[B\(_4\)O\(_5\)(OH)\(_x\)]·yH\(_2\)O. The sum of \(x\) and \(y\) is:

• A. 14
• B. 09
• C. 12
• D. 10

Hint:

Understanding the composition of chemical compounds and their molecular formulas helps in determining the quantities of various components in the compound.

Answer 1

The Correct Option is C

Step 1: Understand the Chemical Formula of Borax Borax has the formula Na\(_2\)[B\(_4\)O\(_5\)(OH)\(_x\)]·yH\(_2\)O, where: - Na\(_2\) is sodium, - B\(_4\)O\(_5\) represents boron and oxygen components, - (OH)\(_x\) is the hydroxide group, - yH\(_2\)O represents water of crystallization. The chemical formula of borax in its most common form is Na\(_2\)B\(_4\)O\(_7\)(OH)\(_4\)·8H\(_2\)O.

 Step 2: Determine \(x\) and \(y\) From the formula Na\(_2\)B\(_4\)O\(_7\)(OH)\(_4\)·8H\(_2\)O: - \(x\) represents the number of hydroxide ions (OH), and there are 4 hydroxide ions, so \(x = 4\). - \(y\) represents the number of water molecules of crystallization, and there are 8 water molecules, so \(y = 8\). 

Step 3: Calculate the sum of \(x\) and \(y\) Now, sum \(x\) and \(y\): \[ x + y = 4 + 8 = 12 \] Thus, the sum of \(x\) and \(y\) is 12.