AnalogRead+mapping ans decimal.

Projects Programming
4

Don't use map(). You don't need it, and for what you're doing, it won't help you.
Just do the arithmetic.
Maybe this would work for you:

// get the reading
int rawReading = analogRead(A0);

// calculate the pH
float pHValue = ((rawReading / 1023.0) * 12.0) + 2.0;

// output
Serial.print("raw reading: ");
Serial.print(rawReading, DEC);
Serial.print("   pH: ");
Serial.println(pHValue, 1);  // one decimal place