If a buffer system containing hydrofluoric acid and fluoride (pKa = 3.17) initially has a pH of 3.22 and base is added until a new pH of 4.69 is obtained, how has the ratio of fluoride to hydrofluoric acid changed?

A. from 1.12 : 1 to 33.1 : 1
B. from 1 : 1.12 to 33.1 : 1
C. from 1 : 1.12 to 1 : 33.1
D. from 1.12 : 1 to 1 : 33.1

a.metals can become magnetic if they have many spinning electrons that create magnetic fields.d.only some metals are attracted by magnets; these metals are called ferromagnetic.

d.wrapping an insulated wire around a metal with ferromagnetic properties and applying an electric current.

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the answer is the first electromagnet (a). this is because it has more coils around the ferromagnetic material. increasing the number of coils increases the surface area in which the metal interacts with the current in the coil. this enables more atoms in the metal to become aligned hence becoming more magnetized.