| Keyword | CPC | PCC | Volume | Score |
|---|---|---|---|---|
| was mustard gas used in ww1 | 0.12 | 0.8 | 3357 | 30 |
| was mustard gas used in ww1 or ww2 | 0.53 | 0.2 | 9435 | 46 |
| what was mustard gas used for in ww1 | 1.33 | 0.5 | 1949 | 64 |
| mustard gas used in ww1 | 1.23 | 0.1 | 6122 | 94 |
| when was mustard gas first used in ww1 | 1.02 | 0.4 | 2926 | 60 |
| who used mustard gas ww1 | 0.6 | 0.7 | 52 | 11 |
| who first used mustard gas in ww1 | 1.48 | 0.9 | 5218 | 43 |
| when was mustard gas used in ww1 | 0.16 | 0.8 | 9387 | 95 |
| what battle was mustard gas first used in ww1 | 0.82 | 0.1 | 5770 | 41 |
| did germany use mustard gas in ww1 | 1.6 | 0.3 | 5734 | 84 |
| did germany use mustard gas in ww2 | 0.31 | 0.2 | 7022 | 64 |
| mustard gas in wwii | 1.55 | 0.8 | 581 | 40 |
| mustard gas in wwi | 1.51 | 1 | 2490 | 11 |
