A student prepares 150.0 mL of 1.40 M HCl using 35.0 mL of a stock solution. What is the concentration of the stock solution? Use M subscript i V subscript i equals M subscript f V subscript f..

answer is a

explanation:

passing a magnet thought the

mixture , because iron gets attracted to magnet .

so here we go

atomic mass

239 + 1 = y + 134 + 3 combine like terms

240 = y + 137             subtract 137 from both terms

240 - 137 = y

103 = y

atomic number

94 = z +54 + 0

94 = z + 54               subtract 54 from both sides.

40 = z

answer

i do not get it   at all