Why was the grave but not the acute accent included in ASCII?

Question

While looking at the Unicode properties (code point, script, block, UTF-8 and UTF-16 encoding, etc.) of some characters, I stumbled upon major differences between ` ("GRAVE ACCENT") and ´ ("ACUTE ACCENT"):

Name          Code point  Script  Block               UTF-8
GRAVE ACCENT  U+000060    Common  Basic Latin         60
ACUTE ACCENT  U+0000B4    Common  Latin 1 Supplement  C2 B4

It seems the ´ is not included in the block "Basic Latin" because it was not included in ASCII. What is the reason for including ` but not ´ in ASCII?

I've taken a look into RFC 20 - ASCII format for Network Interchange where it says:

Column/Row  Symbol  Name
2/7         '       Apostrophe (Closing Single Quotation Mark Acute Accent)
6/0         `       Grave Accent (Opening Single Quotation Mark)

I cannot really make sense out of this. The apostrophe and the acute accent are two quite different characters and the people writing the document most likely knew that. What do these insertions in parentheses even mean?

I've also scanned through ASA X3.4-1963 (the original document) but could not find any reasoning for including `. Is there any?

Answer 1

The apostrophe came first. later, when the grave accent was added, it was decided that the existing apostrophe character could also be used as an acute accent.

Here is a synopsis of the history of these characters:

Mar. 1961 -- The apostrophe character is included in the proposed standard code.

Oct. 1963 -- The grave accent was added to the draft standard, possibly to be used primarily as an accent mark, and it was noted that the apostrophe character could also be used as an acute accent.

This article: Character histories: notes on some Ascii code positions by Jukka (Yukka) Korpela discusses some character history and provides additional references.