Paraffin

This is one of the 117 mis-spellings listed as 'Common difficulties' in the section on 'Spelling' within 'Writing' in UEfAP.

The common spelling problem with paraffin is to decide which consonant to double.

There is a double '-f-'.
    
The '-r-' is single.

Etymological note: the name paraffin is derived from the Latin words parvum 'small' and affinis 'related', referring to the fact that, like all alkanes, paraffin is relatively non-reactive, in chemical terms. (Affinis is also the source pf affinity, which may help some writers to spell the word better.)

Paraffin is the British English equivalent of what American English calls 'kerosene': a liquid mixture, of varying proportions standardized in the reining industry, of hydrocarbons used mostly as fuel for jet engines. (A heavier, more viscous form, liquid paraffin, is used medically as a lubricant, also a laxative; a slightly heavier mixture, the semi-solid soft paraffin, also called petroleum jelly, is used as an emollient; whereas the solid paraffin wax, or hard paraffin, is used in candles and ointments, and for various lubricating purposes.)

• In older texts, paraffin was used to mean what is now usually called alkanes - hydrocarbons with the general formula C_nH_2n + 2. The modern paraffin is a mixture of higher order alkanes.