posted by vivek .
To make 10 mL of 25 mM sodium standard, what volume of 1 M NaCl stock should be used?
None of these
Hmmm. mM? is that milliMolar?
If so, you are diluting it 1/.025 times, or 40 times, so you need 1 part stock, 39 parts water.
1/40 th of 10 ml is 10ml/40= .25ml stock
check my thinking